Answer
a. Yes.
b. No.
Work Step by Step
a. Yes. As discussed on page 930, neutrinos are leptons, and interact only via the weak nuclear force. If a neutrino is among the decay products, the decay occurred via the weak interaction.
b. No. We see from table 32-2 that a decay mediated by the weak interaction could result in a $Z^0$ particle, and no neutrinos.
