Which Statement Does Not Apply to Haptens

Which statement does not apply to haptens?

A) Haptens must bind to a more complex molecule to stimulate an immune response.
B) Haptens are also known as incomplete antigens.
C) Antibiotics such as penicillin are often haptens.
D) Haptens are generally too small to be immunogenic on their own.
E) Haptens are any nonpathogenic substance, rather than a microorganism, which can stimulate an immune response.