The Difference Between a Quark and a Lepton Is

Multiple Choice

The difference between a quark and a lepton is

A) quarks exist in the nucleus; leptons do not.
B) leptons appear in the nucleus; quarks do not.
C) quarks can appear as free particles; leptons cannot.
D) matter is made of quarks; leptons are exchanged to produce forces.
E) none; they are two names for the same particle.