Context: Greg went to a magic show. The magician rubbed a balloon on her hair and then held the balloon against a wall. When the magician released the balloon, Greg was amazed to see that it stuck to the wall! He wonders what factors affect how well balloons stick to different surfaces. So, he decides to design an experiment. He has the following supplies available:
the hair on his own head
a cotton blanket
a wooden door
five rubber balloons
Using only these supplies, which question can Greg investigate with an experiment?
A. Do rubber balloons stick to a wooden door or a metal door longer after being rubbed on his hair?
B. Do rubber balloons or foil balloons stick to the wooden door longer after being rubbed on his hair?
C. Do rubber balloons stick to a cotton blanket or a wooden door longer after being rubbed on his hair?
From the given choices, select the correct answer and reply with the letter of the chosen option.

C