Which best explains why all equilateral triangles are similar?

A. All equilateral triangles can be mapped onto each other using dilations.

B. All equilateral triangles can be mapped onto each other using rigid transformations.

C. All equilateral triangles can be mapped onto each other using combinations of dilations and rigid transformations.

D. All equilateral triangles are congruent and therefore similar, with side lengths in a 1:1 ratio.