A Researcher Wants to Examine the Effect of Fertilizer and the Effect

A researcher wants to examine the effect of fertilizer and the effect of sunlight on the yield of tomatoes.She bought 60 tomato plants at a local garden store.She randomly assigned 30 tomato plants to be planted on the sunny side of the hill and 30 to be planted on the shady side.Within each group of 30 plants,she randomly assigned plants to one of three groups.The first group is grown with no fertilizer,the second group with a small amount of fertilizer,and the third group with a large amount of fertilizer.All tomato plants are planted at the same time and are all treated alike (in terms of how much they are watered,weeded etc) .Each plant is grown to maturity.The total weight of tomatoes obtained from each plant is recorded.The person evaluating the results does not know which tomatoes received fertilizer or which were grown on the sunny side.Within both groups (those grown on the sunny side and those grown on the shady side) tomatoes grown with a large amount of fertilizer yielded the most tomatoes.Determine the nature and scope of the conclusion the experiment can reach.

A) Since the person evaluating the results could have been biased,no conclusion can be reached.
B) Yield may be increased for tomatoes grown with a large amount of fertilizer.
C) For tomatoes grown on the sunny side,yield may be increased for tomatoes grown with a large amount of fertilizer.
D) Since the technician tending to the plants could have been biased,no conclusion can be reached.
E) Yield may be increased for tomatoes grown on the sunny side with a large amount of fertilizer.