Sean wants to know whether monarch butterflies prefer to feed from flowers of a certain color. Sean placed different colored lantana flower plants in separate 1-L terra cotta flower pots. He has a white lantana, purple lantana, orange lantana, yellow lantana, and red lantana. Sean set the pots on his back porch. He then observed the pots for four days and recorded how many visits each of the flower plants received from a monarch butterfly. What is the variable in Sean's experiment?
A.
the time of day the butterflies fed
B.
the color of the flowers
C.
the type of pot the plants were placed in
D.
the type of butterfly visiting the plants