Transposable elements were discovered by

Answer: Option A

Transposable elements were discovered by McClintock.
McClintock went on to discover other such mobile elements, now known as transposons. She also found that depending on where they are inserted into a chromosome these mobile elements could reversibly alter the expression of other genes.
Transposable elements (TEs), also known as "jumping genes," are DNA sequences that move from one location on the genome to another.