Solution:The given figure is
We know that convex polyhedron is one in which the line segment connecting on the surface of a polyhedron totally sits within or on the polyhedron. Otherwise, it is a concave polyhedron.
In the given figure, let us consider two points A & B.
Join the points AB. We get a line segment AB.
The line AB is not totally contained within or on the polyhedron.
So, it is a concave polyhedron
The correct option is (2).