If process P$0$ is switched to process P$1,$ state for P$0$ will be saved into $\_\_\_\_,$ and state from $\_\_\_$ will be reloaded?

$10$

a$.$

PCB$1,$ PCB$0$

b$.$

PCB$1,$ PCB$1$

c$.$

PCB$0,$ PCB$1$

d$.$

PCB$0,$ PCB$0$