What Physical Process Provides the Energy for the Ejection of a Planetary

Multiple Choice

What physical process provides the energy for the ejection of a planetary nebula from a low-mass star?

A) transfer of hydrogen-rich material onto the surface of a white dwarf from its companion in a binary star system
B) helium shell flashes in the helium fusion shell
C) core collapse and the ensuing shock wave
D) collision with another star