The complex function tan h(s) is analytic over a region of the imaginary axis of the complex s-plane if the following is TRUE everywhere in the region for all integers n

A. Re(s) = 0

B. $$I$$m(s) ≠ nπ

C. $$I{\text{m}}\left( {\text{s}} \right) \ne \frac{{{\text{n}}\pi }}{3}$$

D. $$I{\text{m}}\left( {\text{s}} \right) \ne \frac{{\left( {2{\text{n}} + 1} \right)\pi }}{2}$$

Answer: Option D