If tan θ = 1/2 and tan ϕ = 1/3,

D. π/4

Explanation:

According to the question,

$\tan \theta=\frac{1}{2}$ and $\tan \phi=\frac{1}{3}$

We know that,

$\tan (\theta+\phi)=\frac{\tan \theta+\tan \phi}{1-\tan \theta \tan \phi}$

$=\frac{\frac{1}{2}+\frac{1}{3}}{1-\frac{1}{2} \times \frac{1}{3}}=\frac{\frac{5}{6}}{\frac{5}{6}}=1$

$\Rightarrow \tan (\theta+\phi)=\tan \frac{\pi}{4}$

$\Rightarrow \theta+\phi=\frac{\pi}{4}$

Thus, option (D) π/4 is the correct answer.