Polygraph tests

a. are extremely effective in detecting guilt in those who are guilty and innocence in those who are innocent.
b. are difficult to fake.
c. can be fairly accurate when the suspect is naive and the examiner is competent.
d. can be admitted into evidence in all district courts throughout the united states.

Option A

Explanation:

This is one of the easiest method of detecting the truth from someone.

A polygraph test is taken to determine the truthfulness in a story, used to determine if the person in question is actually telling the truth and holding nothing back.

From the above options in the question, option A best explains what a polygraph test is used for. Yes, it is an extreme test in detecting guilt in those who are guilty and innocence in those who are innocent.