Your assessment criteria:
- I will be able to react as fast as possible even to the fastest punch like the jab
- I will take the minimum amount of damage (if any)
- Be in a position to react fast to a counter strike (or attack simultaneously with opponent's strike if possible)
And your defensive options:
dodging, parrying, blocking or stepping back (so that you are out of reach)?
dodging works great if you can do it successfully, but it tends to require more gross movement of the body which means you have to have better timing and anticipation of the attack than the attacker had of your moves; i.e. it only works well if you're a better fighter anyway, and a skillful opponent will make it hard by mixing in feints
parrying/blocking this is easier because your arms and legs are designed to move around your centre of mass faster and more freely - and reach further - than your torso and head and groin (all targets that are hard to get out of the way by dodging); further - if they're trying to have the attack focus at your groin/torso/head and you're meeting it 30/40/50cms away, it probably won't have focus yet: it won't be at maximum force, and the stabilising muscles that keep it on track to the target can't be clenched too hard without slowing down the attack, so it's easier to deflect and pull off course. If your block is predictable and straight into the attack, the attacker may focus there instead of do more damage to your blocking limb. Another problem with blocking is that after contact you may be grabbed or pushed in an unexpected way. For example, one trick is to deliver a low roundhouse kick to get the opponent to lift their leg to jam it, but then you can slow down the kick at the end and pull their jamming leg in an unexpected direction while they're standing on one foot, for example, pulling them across to your open side so you can close the gap and push their blind side (over/behind their shoulders).
stepping back generally makes it harder to counter - you have to have great timing to be just out of reach then return to strike; it can work very well though - many fighters do have that timing. Still, someone may feign and if you lean or slide back and immediately pop back, time a real attack to hit you.
So, dodging under to to the side is perhaps the hardest thing to make great use of, and you may have to compromise your position when doing it, making the counter harder to pull off or less powerful. The other two have elements of cat and mouse, where feints and mixing up the attacks and timing become very important.
One thing that shifts the balance of all this - in my opinion - is the preparation that happens before the attack. If you have a good guard the opponent won't be able to throw an attack straights at you along the shortest/fastest/most explosive path - they'll have to attack around your guard, and you won't have to move your guard much to block or deflect or counter afterwards. Indeed, a good guard should make the threat of your attack a disincentive for them to attack - as when they're trying to go around your guard you can often strike so fast and hard into them that they can't complete a meaningful attack. Further, the footwork you use before they attack should keep you at an awkward angle for them to attack to, so they can't attack properly without first taking a step or rotating their body towards you or whatever - that's more telegraphing and time for you to exploit whatever openings they create and consolidate your own defence, moving somewhere that will require them to make yet another adjustment.
Summarily, active footwork and an active, forward guard that continuously threatens counter strikes and is ready to block minimally in any direction is the most effective defence. By an active guard, I mean you're tracking the position of their limbs and the threats they pose and keeping your guard in the optimal position. So, it's not really any of your options alone, but blocking is part of it and the most versatile, effective option on your list.