If a/b + b/a = \, ( a + b ), then -

Answer: Option A

$$\begin{array}{rl}& \log \frac{a}{b}+\log \frac{b}{a}=\log \left(a+b\right)\\ & \Rightarrow \log \left(a+b\right)=\log \left(\frac{a}{b}\times \frac{b}{a}\right)\\ & \Rightarrow \log \left(a+b\right)=\log 1\\ & So,a+b=1\end{array}$$