Cross probability

can someone explain why this one is A?


we can’t have offspring with ss or SS in their genotype so C) D) and E) are wrong

the SSpp fly will only give one type of gamete: Sp
the ssPp fly will give gametes: half sP and half sp

so offpring will be half SsPp or half Sspp A)

on the test i find it’s worth wasting 1 min doing a quick punnett square to be extra sure of my answer if the question is a little confusing

Hope this helps!!!