When a Massive Star Collapses into a Type II Supernova

When a massive star collapses into a Type II supernova, elements heavier than iron are created. But the amounts of these elements that survive such a collapse are not sufficient to account for the amounts seen in the universe. Where are/were many of them likely produced?

A) Type Ia supernovae
B) the original Big Bang at the origin of the universe
C) collisions of neutron stars
D) nucleosynthesis in the cores of smaller but more numerous stars, like the Sun