i think it is D, she has already constructed the hypothesis and needs is performing the experiment. there is not much of an observation stage because she is looking at a distant end result in a set time frame.
When Went placed the agar block on one side of the decapitated shoot, the shoot curved away from the agar as it grew. This demonstrated that some kind of hormonal signal had diffused into the agar from the coleoptile tips. ... Went's experiment represented the first time that anyone had isolated a hormone from plants.
