3. Consider the instructions that can be divided into four classes according to the CPI (class A, B, C, and D). A processor Pl has a clock rate of 2 GHz. The average number of cycles for each instruction class for PL is as follows: Class A B D CPI on PI 1 2 3 3 Given a program with a dynamic instruction count of 1.0 x 10 instructions divided into classes as follows: 10% class A, 20% class B, 50% class C, and 20% class D. [4 pts] a. Find the clock cycles required. b. Find the execution time of instructions