A function is matched below against an interval where it is supposed to be increasing. Which of the following pairs is incorrectly matched?

- (-∞,1/3] ; 3x
^{2}- 2x + 1 - [2,∞) ; 2x
^{3}- 3x^{2}-12x + 6 - (-∞,∞) ; x
^{3}- 3x^{2}+ 3x + 3 - (-∞,-4] ; x
^{3}+ 6x^{2}+ 6

**Answer**

f(x) = x^{3} + 6x^{2} + 6

f'(x) = 3x^{2} + 12x = 3x(x+4)

f'(x) > 0, x < -4 U x > 0

The interval x < -4 i.e (-∞, -4] matched correctly.

**The correct option is A.**