In the CNO Cycle, Carbon Is Used as a Catalyst

In the CNO cycle, carbon is used as a catalyst for the fusion of hydrogen into helium. This means that

A) three helium nuclei fuse to form carbon.
B) carbon facilitates the reaction but is not consumed in it.
C) carbon boosts the energy from the reaction, which is why massive stars are luminous.
D) carbon breaks apart into three helium nuclei.
E) the reaction produces carbon nuclei in addition to helium.