$\cos\theta = \dfrac{\sqrt{3}}{2} \Rightarrow \theta = 30°$ and $\sin\phi = \dfrac{1}{2} \Rightarrow \phi = 30°$. So $\theta + \phi = 60°$, and $\tan 60° = \sqrt{3}$.
Answer: (A) $\sqrt{3}$
From Table 8.1 (Ch. 8): $\cos 30° = \frac{\sqrt{3}}{2}$ and $\sin 30° = \frac{1}{2}$, so both angles are 30°. Their sum is 60°, and $\tan 60° = \sqrt{3}$. Identify standard angles from the table — this is the key skill tested here.