When Does Conjugation Occur

When does conjugation occur?

A) Conjugation occurs every time an organic molecule has a heteroatom in its structure regardless of hybridization.
B) Conjugation occurs every time an organic molecule has a sequence of three or more sp² hybridized atoms.
C) Conjugation occurs every time an organic molecule has a sequence of three or more sp³ hybridized atoms.
D) Conjugation occurs every time an organic molecule has a sequence of two or more sp² hybridized atoms.
E) Conjugation occurs every time an organic molecule has a ring-type structure.