From this list select the best example of Bias in Sampling.

From this list select the best example of Bias in Sampling.
A . Testing the completeness of cooking a cake but the testers cannot agree on how to measure internal temperature
B. Testing the sharpness of a razor blade while the sample of 500 are from the same model razor
C. Testing the weight of participants at a wrestling event and only measuring those who finished second or better
D. Testing a hand-held GPS models for durability using samples only from Nokia Model P120

Answer: C