Answer:
d
Step-by-step explanation:
The dashes on the sides of the triangles mean that they are equal in length.
Isosceles triangle: 2 sides of equal length
Equilateral triangle: 3 sides of equal length
Triangle a doesn't have any dashes, so all the sides are different length.
Triangle b has 2 sides that each have the same number of dashes, so these sides are equal in length → Isosceles triangle
Triangle c has 2 sides that each have the same number of dashes, so these sides are equal in length → Isosceles triangle
Triangle d has 3 sides that each have the same number of dashes, so these sides are equal in length → Equilateral triangle
