**Correct option (b),(c)**

**Explanation :**

(A) It is given that f: R→R, g: R→R and h: R→R are differentiable functions.

Now, f(x) = x^{3} + 3x+ 2 Differentiating w.r.t. to x, we get

f '(x) = 3x^{2} + 2

Also,

g(f(x)) = x

Now,

Now,

Hence, option (A) is incorrect.

(B) For all x ∈ R :

Therefore,

Hence, option (B) is correct.

Hence, option (D) is incorrect