When a creature with an initial power of 1 and toughness of 3 is given +0/+1 and then its power and toughness are switched, what becomes its actual power and toughness?

To understand the reasoning behind the correct answer, let's break down the situation step by step:

Initially, the creature has a power of 1 and a toughness of 3, denoted as 1/3. When the creature receives a +0/+1 effect, its toughness increases by 1, changing its stats to 1/4. This is the first adjustment.

Next, when the power and toughness are switched, the creature’s power becomes whatever its toughness was, which is now 4, and its toughness becomes the original power of 1. Consequently, the creature ends up with 4/1 after this switch.

Therefore, the outcome at each phase—first changing the stats to 1/4 and then switching the power and toughness—results in the creature having an actual power and toughness of 4/1 after these modifications.

The influence of the creature's initial stats, the effects applied to it, and the final switch of power and toughness all cohesively lead to the conclusion represented in the correct answer.