Question

what is any of a number of subatomic particles carrying a fractional electric charge, postulated as building blocks of the hadrons. (hint: vocab word)
star
black hole
quark

Explanation:

Quarks are subatomic particles with fractional electric charges and are considered building - blocks of hadrons. Stars and black holes are not subatomic particles with fractional charges and building - blocks of hadrons.

Answer:

C. quark