A computer system has a cache (L1). For a given program with 1 million instructions, Ll cache miss rate is 10%. Average instruction execution time is 40 ns. For all misses, time to take a block from main memory into the cache is 600ns. a. Calculate the time to execute this program. Give your result in milliseconds. b. You need to improve the performance of this system. You have 2 alternatives: either you can replace the Li cache by a new one that is 2 times faster than the existing one or you can improve the main memory access time 2 times faster. Which one would you choose? Calculate the execution time of the program for both cases in order to prove your