Write a balanced nuclear equation for positron emission by manganese-52.

a) Mn⁵2 -> Cr⁵2 + e⁺
b) Mn⁵2 -> Fe⁵2 + e⁻
c) Mn⁵2 -> Cr⁵2 + e⁻
d) Mn⁵2 -> Fe⁵2 + e⁺