Which Component in the Core of a Star Undergoing Helium

Which component in the core of a star undergoing helium fusion leads to the behavior known as the "helium flash?"

A) neutrinos, since it is this component that, in interacting with helium nuclei, triggers the helium flash
B) helium, since its density has to be above a certain limit to trigger this explosive event
C) electrons, since they control the pressure, and their pressure does not depend on temperature. Under these conditions, buildup of heat can occur without leading to the normal gas expansion and the resulting thermal equilibrium.
D) remnant hydrogen since loss of this component allows uncontrolled helium burning rather than a uniform rate of energy production