Why Are Higher Gas Temperatures in the Core of a Star

Why are higher gas temperatures in the core of a star required to produce nuclear fusion of helium compared with the temperature required for nuclear fusion of hydrogen?

A) The helium nuclei need to be moving faster to avoid the more numerous and faster hydrogen nuclei, with which they can combine with no energy generation.
B) Higher speeds are needed between two helium atoms to overcome the shielding effect of the two electrons around the nucleus compared with the one electron per nucleus of hydrogen.
C) Higher atomic speeds are required to strip off two electrons per helium atom rather than one electron per atom for hydrogen before fusion can take place.
D) Higher collision speeds are needed to overcome the extra electrostatic repulsion between doubly charged helium nuclei.