Answer
The $L_\mu$ conservation law is violated.
The energy conservation law is violated.
Work Step by Step
The $\mu^+$ has $L_{\mu} = -1$
The $\pi^+$ has $L_{\mu} = 0$
The $\nu_\mu$ has $L_{\mu} = +1$
Therefore, the $L_\mu$ conservation law is violated.
The $\mu^+$ has energy $105.7~MeV$
The $\pi^+$ has energy $139.6~MeV$
The $\nu_\mu$ has energy $1\times 10^{-7}~MeV$
Therefore, the energy conservation law is violated.
