Assume the system as question 1. Assume cache is initially empty, i. e., all 4 cache blocks are invalid. Consider the memory reference sequence: D6, 58, D8, 9A, DE, 5C.(a) Indicate if it is a hit or misss for each memory reference if it is direct-mapped cache. What is the miss ratio?(Hint: Three memory block 50-5F, 90-9F, and D0-DF would be copied to the same block in the cache because their block index is the same, 1.)(b) Indicate if it is a hit or misss for each memory reference if it is fully-associative cache? What is the miss ratio?(c) Indicate if it is a hit or misss for each memory reference if it is 2-way set-associative cache? What is the miss ratio? Assume to replace the block which has been used "least recently".(Hint: Three memory block 50-5F, 90-9F, and D0-DF would be copied to the same "set" in the cache because their "set" index is the same, 1. In each set, there are 2 blocks.)