Answer
See explanation below.
Work Step by Step
Because there are 5 d orbitals, 5 unpaired d electrons are available. Manganese have 5 unpaired d electrons. Its electronic configuration is [Ar] 4s2 3d5.
Mn ion, Mn2+ have 5 unpaired electrons even in its ionic form. The electronic configuration of Mn2+ is [Ar]3d5.