One necessary condition for deadlock is , which states that there is a chain of waiting processes whereby P0 is waiting for a resource held by P1, P1 is waiting for a resource held by P2, and Pn is waiting for a resource held by P0.

Circular wait.

Explanation:

Of all four necessary conditions of deadlocks encountered so far, i can easily ascertain that the circular wait is the perfect match for the case above.

The circular wait algorithm processes are required to access or use a resource a specific order, so when one process is finished employing a resource, the following process within the queue takes the resource, uses it after which it'll give to the following waiting process in queue and also the sequence continues.

Assuming you've got three process named A, B and C and that they must use a resource in an exceedingly manner that circular wait are going to be implemented, process A will take the resource and use it for a substantial amount of your time and when it's done process B will take the resource and use it for a substantial amount of your time so hand the resource to process C. Process C will hand the resource to A after it's finished it, and therefore the process continues that way.

answer; the cpi;