Specify either "Write Through" or "Write Back" as the policy which best corresponds to each of the conditions below.

1) Main memory is kept coherent (consistent with cache contents) at all times.
2) Utilizes dirty bits.
3) All sw $t1,0($s0)(i.e. store word) instructions become slowed down to execute at the access time of main memory.
4) References for those sw $t1,0($s0)instructions which are hits will operate at the access time of cache.