One example of scientists taking different approaches that lead to the same result is
a. two scientists testing different hypotheses about the same observation.
b. two scientists repeating a third scientist’s experiment as published.
c. two scientists working on one experiment at the same time in different labs.
d. two scientists performing one experiment at different times in the same lab.

I think the correct answer would be option A. One example of  scientists taking different approaches that lead to the same result would be two scientists testing different hypotheses about the same observation. Two different hypotheses would mean that they have different experimental design thus their approach to attaining there hypothesis would be different assuming that their subjects are the same. Although, the experiments were different or their methods are different, it would be possible that they would have the same observations since they have the same topic or subject.