Which experiment would most likely contain experimental bias?

Question

A.
A student tests the attraction of bees to flowers by placing four different flowers in the same location and counting how many bees visit each.
B.
A lab performs a test by giving bacterial colonies the same amount of different antibiotics and growing them under the same conditions.
C.
A chemistry class performs an experiment in which each reaction has the same amount of starting material and begins at the same temperature.
D.
A company that makes pain relief medication tests the effectiveness of their own medicine compared to that of three other brands.

Answer 1

D. A company that makes pain relief medication tests the effectiveness of their own medicine compared to that of three other brands.