"With Genetically Different Animals, There's Always the Possibility That the Results

"With genetically different animals, there's always the possibility that the results of experiments are due to variations among animals rather than to whatever is being tested. Genetically identical research animals would therefore be a boon to research because scientists could be more confident of their research results." Which of the following best states the primary issue discussed in the passage?

A) whether scientists need to be more confident of their research results
B) whether genetically identical research animals would be a boon to research
C) whether results of experiments are due to variations among animals or to whatever is being tested
D) whether experimentation on animals should continue