Response B is better because it correctly identifies the visible icon (dark hooded helmet with red glow and quantity “1” in the corner) as the Satanic item from Dota 2, while Response A wrongly identifies it as a Dead by Daylight throwing-knife icon. B therefore accurately answers “what is this”.

Response B nails it because it spots the actual icon you can see (that dark hooded helmet with the red glow and the little "1" in the corner) and correctly calls it out as the Satanic item from Dota 2. Response A totally misses the mark by saying it's some throwing-knife icon from Dead by Daylight, which is just wrong. So B actually answers "what is this" the right way.