Answer:
Option C. is the correct answer.
Explanation:
Since in the given Venn diagram "Blue circle" is contained in a "purple circle".
Blue circle represents Equilateral triangles and purple color circle represents isosceles triangle.
Since by this Venn diagram, equilateral triangles are contained in isosceles triangle then we can conclude that all equilateral triangles are isosceles triangle.
Therefore, option C. if shape is an equilateral triangle, then it is an isosceles triangle is true.