The Fourier series representation of an impulse train denoted by
$$s\left( t \right) = \sum\limits_{n = - \infty }^\infty {\delta \left( {t - n{T_0}} \right)} \,{\rm{is}}\,{\rm{given}}\,{\rm{by}}$$

A. $${1 \over {{T_0}}}\sum\limits_{n = - \infty }^\infty {\exp \left( { - {{j2\pi nt} \over {{T_0}}}} \right)} $$

B. $${1 \over {{T_0}}}\sum\limits_{n = - \infty }^\infty {\exp } \left( { - {{j\pi nt} \over {{T_0}}}} \right)$$

C. $${1 \over {{T_0}}}\sum\limits_{n = - \infty }^\infty {\exp } \left( {{{j\pi nt} \over {{T_0}}}} \right)$$

D. $${1 \over {{T_0}}}\sum\limits_{n = - \infty }^\infty {\exp } \left( {{{j2\pi nt} \over {{T_0}}}} \right)$$

Answer: Option A