Task: Question Answering
Input (English): The muon decays with a characteristic lifetime of about 10^-6 second into an electron, a muon neutrino, and an electron antineutrino. The muon is forbidden from decaying into an electron and just a single neutrino by the law of conservation of
(A)charge (B)mass (C)energy and momentum (D)lepton number
Output (English): D