The correct option is C If the diagonals of a quadrilateral are perpendicular bisectors of each other then it is a rhombus.
If the antecedent and consequent in a given conditional statement are interchanged, the resulting statement is called the converse of the given statement.
The converse of the conditional statement "If a quadrilateral is a rhombus then its diagonals are perpendicular bisectors of each other" is, "If the diagonals of a quadrilateral are perpendicular bisectors of each other then it is a rhombus."