Classifying subatomic particles by composition and type

Steps:

• Define hadrons as composite particles formed by quarks bound by the strong force.
• Distinguish baryons as hadrons with three quarks (standard) and mesons as quark-antiquark pairs.
• Identify fundamental particles as elementary, including leptons like electrons and neutrinos, which do not contain quarks.
• Evaluate each choice against these definitions to find the accurate statement.

Why C is correct:

• Electrons are elementary particles in the lepton family, not composed of quarks, per the Standard Model.

Why the others are wrong:

• A: Standard baryons have three quarks, but exotic ones like pentaquarks have five, so not exclusively three.
• B: Mesons are hadrons but consist of one quark and one antiquark pair, not three quarks.
• D: Neutrinos are fundamental leptons but not hadrons, which are quark-based composites.

Final answer: C