If $D,\;E $ and $F$ are the mid points of the sides $AB, \;BC$ and $CA$ of an equilateral triangle $ABC$ , then $\Delta DEF$ is a _________ triangle.

Question

$\begin{array}{1 1} (a)\; \text{equilateral triangle} \\ (b)\; \text{isosceles triangle} \\ (c)\; \text{scalene triangle} \\ (d)\; \text{right triangle} \end{array}$