Read the Following Scenario, and Answer the Questions Below

Multiple Choice

Read the following scenario, and answer the questions below.

THE EXPERIMENT:
Researchers wanted to determine whether pesticide Z is effective at killing grasshoppers that typically invade cornfields. Two 10- acre cornfields located 1 mile apart were chosen. The cornfield to the west was sprayed only with water. The cornfield on the east received the same amount of water with a 10% solution of pesticide Z. The number of grasshoppers in the fields was recorded every week for 10 weeks.

RESULTS:
The number of grasshoppers in the west field treated only with water doubled after 10 weeks.
The number of grasshoppers in the east field treated with pesticide Z declined by 50% after 10 weeks.

-What was the independent variable in the above experiment?

A) The location of the fields
B) The number of grasshoppers receiving the pesticide
C) The number of grasshoppers after 10 weeks
D) Whether pesticide Z was applied