$5.$ Consider the methods used by processes P$1$ and P$2$ for accessing their critical sections whenever needed as given below. The initial values of shared Boolean variables S$1$ and S$2$ are randomly assigned. Which one of the following statements describes the properties achieved?Method used by P$1$Method used by P$2$While$($flag$!=0)$;Flag$=1$;CS$()$;Flag$=0$;While$($flag$!=0)$;Flag$=1$;CS$()$;Flag$=0$;a$)$ Mutual exclusion but not progressb$)$ Progress but not mutual exclusionc$)$ Neither mutual exclusion nor progressd$)$ Both mutual exclusion and progress