What Is the Difference Between a "Helium Flash" and a "Helium

What is the difference between a "helium flash" and a "helium shell flash"?

A) A helium flash occurs when the core becomes supported by electron-degeneracy pressure; a helium shell flash occurs when the helium shell becomes supported by electron-degeneracy pressure.
B) All stars with mass less than 8 times the mass of the Sun undergo a helium flash, but only those between 2 and 8 times the mass of the Sun undergo a helium shell flash.
C) A helium flash occurs just once; a helium shell flash can repeat many times.
D) A helium flash results in a supernova; a helium shell flash results on a planetary nebula.