The correct option is (d) \(\frac{a}{a+1}\)
For explanation I would say: The given equation can be solved using L-Hospital’s Rule,
\(\frac{d(ax)}{dx}=a, \frac{d(ax+x)}{dx}=a+1\)
\(\lim_{x\to 0}\frac{ax}{ax+x} → \lim_{x\to 0}\frac{a}{a+1} → \frac{a}{a+1}\)