I believe it's D don't take my word for it.
Hallo~~
Your question is related to genetics.
Have you ever done a Punnett Square? This question forces you to make one. If your cross a homozygous type A (AA) and homozygous type O (OO) you should get 100% AO. Understanding genetics, an AO gene means a type A blood. Therefore, it's 100% type A blood (AO).
Assuming the graph that shows plant groups B and C have a lower growth rate than group A, this shows that every plants needs a certian amount of sunlight to grow. Since they get their energy from the sun, it is the most crucial to a plants survival. If plants dont get the energy they need to live, as producers, primary consumers dont get get energy from producers. If primary consumer cant get energy, neither can secondary consumer and so forth.