Under What Condition Would Directed Enzyme Evolution Be More Appropriate

Under what condition would directed enzyme evolution be more appropriate that site-directed mutagenesis?

A) When attempting to produce an altered enzyme.
B) When you want the enzyme to catalyze a different type of reaction.
C) If very little is known about the enzyme structure.
D) If you want to permanently disable the enzyme.
E) If you want the enzyme expressed in a different organism.