It can be inferred from the passage that hypernovae are best at explaining which of the fo

A．What are the consequences of GHBs sweeping up the external medium that surrounds black holes？

B．What role does compact-star coalescence play in the GHB phenomenon？

C．How do normal-duration GHBs come into existence？

D．Of what does the matter leftover from the collapse of a star consist？

E．What sorts of GHBs are likely to be produced by the collapse of the Earth's sun？