Fill in SPIN or BLOCK in the following sentences: A. On a un…

Fill in SPIN or BLOCK in the following sentences: A. On a uniprocessor system, if thread T1 tries to lock a mutex that has already been locked by T2, by default T1 will . B. On a multiprocessor system, if thread T1 tries to lock a mutex that has already been locked by T2, by default T1 will .C. Given the adaptive mutex proposed in the Solaris papers, if thread T1 tries to lock a mutex that has already been locked by T2, T1 will if T2 is currently executing.D. Given the adaptive mutex proposed in the Solaris papers, if thread T1 tries to lock a mutex that has already been locked by T2, T1 will if T2 is not currently scheduled.