The Heavier Noble Gases Are More Reactive Than the Lighter

The heavier noble gases are more reactive than the lighter ones because

A) the lighter noble gases have complete octets.
B) the heavier noble gases are more abundant.
C) the lighter noble gases exist as diatomic molecules.
D) the heavier noble gases have low ionization energies relative to the lighter ones.
E) the heavier noble gases have greater electron affinities.