Let$f\left(x\right)=$  $\left\{\begin{array}{l}(15-3\mathrm{b})\left\{\mathrm{x}\right\}-({\mathrm{b}}^2-4\mathrm{b}-5)\mathrm{sgn}(\mathrm{x}+1), \frac{-\mathrm{\pi }}{2}<\mathrm{x}<0\\ \mathrm{k}(\left[\mathrm{x}\right]+[-\mathrm{x}]), 0\le \mathrm{x}\le \mathrm{\pi }\\ \frac{(\mathrm{a}+2\mathrm{cosx})(1+\mathrm{tanx})}{\ln (1+{\mathrm{\pi }}^2-2\mathrm{\pi x}+{\mathrm{x}}^2)}, \mathrm{\pi }<\mathrm{x}<\frac{3\mathrm{\pi }}{2}\end{array}\right.$
where [y] , {y} and sgn (y)  denote greatest integer function, fractional part function and signum function of y respectively. 

LIST-I		LIST-II
P)	If f is continuous in  $\left(\frac{-\pi }{2},0\right)$, then the value of  b is	1)	0
Q)	If f is continuous at x = $\pi$, then the value of  $(a+k)$  is	2)	1
R)	If f is continuous in  $\left(\frac{{\displaystyle -\pi }}{{\displaystyle 2}},\pi \right),$ then the value of  $(b+k)$ is	3)	5
S)	If f has exactly four points of discontinuity in  $\left(\frac{{\displaystyle -\pi }}{{\displaystyle 2}},\frac{{\displaystyle 3\pi }}{{\displaystyle 2}}\right),$ then  $(a+b+k)$ is equal to	4)	6