Answer: B) triangle
Explanation:
Given: A slice is made parallel to the base of a triangular pyramid.
A triangular pyramid is a pyramid having a triangular base. A triangular pyramid have congruent equilateral triangles for each of its faces.
Since, the base of the triangular pyramid is a triangle .
So if slice is made parallel to the base of a triangular pyramid then the shape of the cross-section is in the shape of a triangle.