A Neutron Makes a Better "Nuclear Bullet", for Fissioning a Nucleus

A neutron makes a better "nuclear bullet", for fissioning a nucleus, than does a proton. This is because

A) it is easy to accelerate neutrons to high speeds in nuclear accelerators.
B) the negative charge on the neutron attracts it to the nucleus.
C) unlike the proton, the neutron is not repelled by the charge on the nucleus.
D) protons do not feel the strong nuclear force and thus do not interact appreciably with the nucleus.
E) neutrons are so much more massive than protons.