Which one of the following is an LC immittance function?

A. $$Z\left( s \right) = \frac{{Ks\left( {{s^2} + 4} \right)}}{{\left( {{s^2} + 1} \right)\left( {{s^2} + 3} \right)}}$$

B. $$Z\left( s \right) = \frac{{{s^5} + 4{s^3} + 5s}}{{3{s^4} + 6{s^2}}}$$

C. $$Z\left( s \right) = \frac{{K\left( {{s^2} + 1} \right)\left( {{s^2} + 9} \right)}}{{\left( {{s^2} + 2} \right)\left( {{s^2} + 10} \right)}}$$

D. $$Z\left( s \right) = \frac{{2\left( {{s^2} + 1} \right)\left( {{s^2} + 9} \right)}}{{s\left( {{s^2} + 4} \right)}}$$

Answer: Option D