Answer:
(c) It has exactly four faces that are triangles
(d) It has 4 vertices
(f) It has 6 edges
Explanation:
You want to identify 3 true statements about a triangular pyramid.
Figure
An image of a triangular pyramid is attached.
The base is one triangular face. Each of its three edges is the base of a lateral triangular face, so there are a total of 1+3 = 4 triangular faces.
The base triangle has 3 vertices. The lateral triangular faces meet at another vertex, for a total of 3+1 = 4 vertices.
The base triangle has 3 edges. Each of the 3 base vertices joins the fourth vertex with an additional edge, for a total of 3+3 = 6 edges.
A triangular pyramid has 4 faces, 4 vertices and 6 edges.