Answer:
Option A
Explanation:
Given f(x) = $\frac{4x^{2}+1}{x}$
Thus f'(x) = 4 - $\frac{1}{x^{2}}$
f(x) will be decreasing if f '(x) < 0
Thus 4 - $\frac{1}{x^{2}}$ < 0
→ $\frac{1}{x^{2}}$ > 4 → $-\frac{1}{2}<x<\frac{1}{2}$
Thus interval in which f(x) is decreasing, is $\left(-\frac{1}{2},\frac{1}{2}\right)$
