Four complexes are given :

(P) ${\left[\mathrm{CoCl}{\left({\mathrm{NH}}_3\right)}_5\right]}^{2+}$ (Q) ${\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\left({\mathrm{H}}_2\mathrm{O}\right)\right]}^{3+}$

(R) ${\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]}^{3+}$ (S) ${\left[\mathrm{Co}(\mathrm{CN}{)}_6\right]}^{3-}$

All of them exhibit at least one of the following 4 colours viz, violet, red, yellow orange, pale yellow. One of them absorbs light in the U.V. region. Choose the correct statement(s).