Mrs. Richardson performed an experiment on how the type of music affected plant growth. She sets up an experiment playing rock music, jazz music, country music, and rap music to fern plants. She also has a fern plant that she puts in a quiet room. She measures how tall the plants have grown after 4 weeks. They all received the same amount of water and light.

What is the dependent variable?
a
Rock, jazz, country, rap, and no music
b
Amount of water and light
c
Type of music
d
Plant growth