Which solid figure has nine edges?

rectangular pyramid
octagonal pyramid
rectangular prism
triangular prism

Option D.

Step-by-step explanation:

A triangular prism has 5 faces, 2 triangular faces and 3 rectangular faces.

If we calculate the edges of each face then we get

2 triangular faces = 6 edges

and 3 rectangular faces have edges = 3, other edges of the rectangular faces are common with the triangular faces.

Therefore, total number of faces = 6 and total number of edges = 9 will be in a triangular prism.

Option D. triangular prism is the answer.