The manganate and permanganate ions are tetrahedral, due to

the $\mathrm{\pi }$ -bonding involves overlap of d -orbitals of oxygen with d -orbitals of manganese

the $\mathrm{\pi }$ -bonding involves overlap of p -orbitals of oxygen with d -orbitals of manganese

there is no $\mathrm{\pi }$-bonding

the $\mathrm{\pi }$ -bonding involves overlap of p -orbitals of oxygen with p -orbitals of manganese.