A. A relation R on a set A is called an equivalence relation, if it is reflexive, symmetric and transitive.

B. The function f: R→ R defined by () x f x e = is not one-one.

C. The one-one function is also known as injective function.

D. The onto function is also known as subjective function.

E. A function f: X→Y is said to be many-one, if two or more than two elements in set X have the different image in set Y.

 Choose the correct answer from the option given below:

A, C, D only 

A is correct

B. f(x) = e^x is a one-one function.

∵ f'(x) = e^x > 0 ∀X ∈ R.

C & D options are also correct.

So option 1 is correct i.e., (A, C, D only)