Involve probation/prison breaks
I think it would either be c or d...
The answer to this question would be: increased food height
Giraffe becomes tall because its food height is increased. In this case, the environmental pressure on Giraffe would be the increased height of the food.
The taller giraffe has access to higher food. Then, the giraffe with the higher chance of survival in this scenario would be the giraffe with a taller height.
C.The density of ice is less than the density of water.
A dwarf is a recessive trait. In order for the plant to be shorter, it would have to have 2 recessive alleles. The plant is also purebread so it wont contain the tall allele. The gametes that are possible are tt.