Which of the Following Would Be the Least Likely Result

Which of the following would be the least likely result of gene duplication?

A) The gene produces less of its product than it did before duplication.
B) The two copies of the gene are expressed at different stages in the development of the organism.
C) As a result of evolutionary divergence, one copy retains its original function, and the other copy acquires a different function.
D) One copy remains functional, and the other copy evolves into a functionless pseudogene.
E) All of the above are about equally likely results.