One necessary condition for deadlock is $\_\_\_\_\_\_,$ which states that there is a chain of waiting processes whereby P$0$ is waiting for a resource held by P$1,$ P$1$ is waiting for a resource held by P$2,$ and Pn is waiting for a resource held by P$0.$

A$.$ hold and wait

B$.$ mutual exclusion

C$.$ circular wait

D$.$ no preemption