A quadrilateral whose opposite sides and all the angles are equal is a
Rectangle
The correct answer is (a) rectangle
Explanation :
A rectangle is a type of quadrilateral that has its parallel sides equal to each other and all four vertices are equal to . Hence, it is also called an equiangular quadrilateral.
Properties of rectangle
Thus, A quadrilateral whose opposite sides and all the angles are equal is a rectangle.
Hence, the correct option is (a)