In the Above Scenario, Why Did Susan Place the Plants

Multiple Choice

In the above scenario, why did Susan place the plants in a greenhouse and control the amount of sunlight and temperature?

A) Keeping any factor that can influence a plant's growth, other than fertilizer, equal to all plants, ensures that if there is a difference at the end, it will most likely be due to the fertilizer.
B) It was an easy place to keep the plants.
C) It did not make a difference. The fertilizer would have influence growth even if the plants were part in sunlight and part in shade.
D) The plants would have adapted to the situation no matter if the temperatures is different.