What is a nova?

A nova is a sudden increase in the apparent brightness of a star.
Novae are associated with white dwarf stars in binary systems.
The process of mass transfer from a companion star to a white dwarf can trigger a nova.
Novae are less powerful than supernovae.
a) Only statements 1 and 2 are correct.
b) Only statements 2 and 3 are correct.
c) Only statements 1, 2, and 3 are correct.
d) All statements are correct.