(a) A CPU (Intel 80486 of the early 90s) operates at 25MHz. What is the period of a cycle in ns ? (This is nanoseconds, a proper writing of units.) (b) The same CPU as (a) has access to memory with memory access time 80ns. How many CPU cycles does this correspond to ? (c) A CPU Intel Xeon Gold 6248) operates at 2.5GHz. What is the period of a cycle in ns ? (d) The same CPU as (c) has access to memory with memory access time 80ns. How many CPU cycles does this correspond to