Quark transformation in neutron beta decay

Steps:

• Neutron has quarks udd; proton has uud, so one d quark changes to u quark.
• Beta minus decay emits electron (β) and antineutrino (ν̄) via weak force.
• The down quark transforms: d → u + W⁻ boson.
• W⁻ decays to β + ν̄, completing the quark change.

Why B is correct:

• Not applicable; B describes u → d transformation with positron (p) and neutrino (ν), matching beta plus decay (proton → neutron + β⁺ + ν), not neutron decay.

Why the others are wrong:

• A: Correct quark change (d → u) and antineutrino, but p indicates positron instead of electron (β).
• C: Wrong quark direction (u → d); uses β (correct particle) but wrong neutrino (ν instead of ν̄).
• D: Wrong quark direction (u → d); p is positron, ν̄ is correct antineutrino but irrelevant here.

Not enough information: No option fully matches d → u + β + ν̄.

Final answer: None of the options