f : R → R be a differentiable function x ∈ R. If tangent drawn to the curve at any point x ∈ (a, b) always lie below the curve then:

$f'(x)>0,f''(x)<0\,\,x∈ (a, b)$ $f'(x)<0,f''(x)<0\,\,x∈ (a, b)$ $f'(x)>0,f''(x)>0\,\,x∈ (a, b)$ None of these

$f'(x)>0,f''(x)>0\,\,x∈ (a, b)$

Checking the options: (A) f'(x) > 0 f''(x) < 0 Not satisfactory (B) f'(x) < 0 f''(x) < 0 Not satisfactory (C) f'(x) > 0 f''(x) > 0 Satisfactory ⇒ (C)