Answer:
The correct option is;
3. Theories need to undergo peer-review
Explanation:
Within the scientific community, a theory has to be peer-reviewed by subject matter experts before it can be normally considered a valid theory. The peer-review process is one in which another scientific expert on the subject analyze, study, and repeat the experiments in the same conditions as stated in a publication submitted to a journal as a theory. The peer-review process aims to confirm the theory. A discovery which survives the peer review process will be considered a scientific theory and can then be expanded upon.