Imitative Polyphony Occurs When

Imitative polyphony occurs when:

A) various musical lines are heard one after another with the same melody or similar melodies.
B) the main melody is heard in one line and the other parts have clearly less important material, forming an accompaniment to the melody.
C) all musical lines are heard simultaneously, but each has a different melody.
D) all voices or parts are heard simultaneously with the same melody.