Ross is conducting an investigation in which he has grown three bean plants in three different pots. Each pot is similar in size and contains the same amount and type of soil. He watered Pot 1 with 50 mL of water per day, Pot 2 with 70 mL of water per day, and Pot 3 with 100 mL of water per day. He put the pots on a sunny windowsill and measured the growth of each plant after a week. He recorded his observations.

Which question is Ross trying to answer through this scientific investigation?

A. How does the amount of water affect the growth of bean plants?
B. How does sunlight affect the amount of water absorbed by bean plants?
C. How does the amount of garden soil in which bean plants are grown affect their size?
D. How does the type of soil affect the growth of bean plants?