4. Consider three different processors P1, P2, and P3 executing the same instruction set. P1 has a 3 GHz clock rate and a CPI of 1.5. P2 has a 2.5 GHz clock rate and a CPI of 1.0. P3 has a 4.0 GHz clock rate and has a CPI of 2.2. (a) Which processor has the highest performance expressed in instructions per second? (b) If the processor Pl execute a program in 10 seconds, find the number of cycles and the number of instructions. (c) We are trying to reduce the execution time by 30% for P1, but this leads to an increase of 20% in the CPI. What clock rate should we have to get this time reduction for P1