6. Given a prefix expression “+ + (9) × (8) (7) × + × (6) (5) (4) (3)”, please calculate the result.(A) 167 (B) 147 (C) 127 (D) 117 (E) 107

3. For a specific CPU design, there are three instruction classes as depicted in Table 1 and run at a clock rate of 100 MHz.For a given program, a compiler can produce the following executed instruction counts as depicted in Table 2. Please calculate the average CPI of this compiler.(A) 4(B) 2(C) 1.25(D) 0.5(E) All of the above are wrong.