Zoe says an equilateral triangle is always an acute triangle, but an acute triangle is never an equilateral triangle. Which statement explains whether Zoe is correct or not? Select one:
a. Zoe is not correct because equilateral triangles are acute triangles with three sides of equal length. Acute triangles can sometimes be equilateral triangles.

b. Zoe is not correct because equilateral triangles have three acute angles. Acute triangles have three acute angles, so acute triangles are always equilateral triangles.

c. Zoe is correct because equilateral triangles have three sides of equal length, and acute triangles have three sides of different lengths.

d. Zoe is correct because equilateral triangles have three acute angles. Acute triangles have one acute angle, so an acute triangle cannot be an equilateral triangle.