The actual geometry of is:
V-shape
The explanation for the correct option
Option(C) :The actual geometry is trigonal planar:
The ion is trigonal planar with an bond angle of c.
The explanation for the incorrect option:
Option A:
Planar is a molecular geometry model in which one atom at the centre and three atoms at the corner of an equilateral triangle are called peripheral atoms all in one plane. The bond angle is .
For example:-
Option B:
Linear molecular geometry describes the geometry around a central atom bonded to two other atoms or ligands which is placed at an angle of .
For example:-
Option D:
Tetrahedral is a molecular shape that occurs when there are four bonds and no lone pairs in the molecule's central atom.
The atoms bonded to the central atom are located at the four corners of a tetrahedron with angles between them.
For example:-
Thus the correct option is option (C): trigonal planar.