1. (26 pts) Given 256 GB of physical memory, a 2-way set associative cache that is 128 KB in size with a block offset of 4 bits, answer the following: (2 pts) How many bits used for the index of the cache? a. b. (2 pts) How many bits required in the cache for the tag? c. (2 pts) How many rows does this cache have? d. (2 pts) How many bytes of memory are required to store just the valid bit alone