What Is the Missing Particle X in the Reaction $\bar { v } _ { \mu } + \mathrm { P } \rightarrow \mathrm { n } + \mathrm { X }$

Multiple Choice

What is the missing particle X in the reaction $\bar { v } _ { \mu } + \mathrm { P } \rightarrow \mathrm { n } + \mathrm { X }$ ?

A) e⁺
B) $\tau$ ⁺
C) $\mu$ ⁺
D) $\pi$ ⁺
E) p