What Is the Particle X in the Reaction $\mathrm { p } + \overline { \mathrm { p } } \rightarrow \pi ^ { + } + \mathrm { X }$

Multiple Choice

What is the particle X in the reaction $\mathrm { p } + \overline { \mathrm { p } } \rightarrow \pi ^ { + } + \mathrm { X }$ ?

A) $\pi$ ⁰
B) $\pi$ ^-
C) e^-
D) $\overline { \mathrm { p } }$