15. Consider a computer system with a direct-mapped cache and 16-bit addresses where the bits are allocated as follows: Tag 15-8 Index 7-6 Byte offset 5-0 a) What is the cache block size in bytes? b) How many entries (blocks) does the cache have? (5%) (5%) c) Starting from an empty cache, determine whether each of the following block accesses is a miss or a hit, and calculate the hit ratio in the cache: 15, 7, 10, 7, 15, 2, 6, 2. (10%)