Choose the correct statement with respect to mutation in a wild gene. 

• A

  A modified form of gene product may be rarely functionally more efficient than unmodified form the gene (wild allele).

• B

  A modified form a gene never be functionally equal to the unmodified form of allele

• C

  A modified form a gene always forms a gene product.

• D

  A modified form a gene always forms a non-functional gene product