Reverse polish notation is a system of formula notation without brackets or special punctuation. To evaluate (A ∗ B) + (C ∗ D / E): First avoid brackets and punctuation and convert it into postfix form i.e. AB+CDE/*+ Now push AB On * pop AB and perform A * B. Now push back the result(say it X). Push CDE. On / pop DE and push back the result(say it Y). On * Pop CY and perform * operation and push the result(say it z). On + pop XZ and perform + opeeration and and push back the final answer. Above computation include 5 PUSH and 4 POP instructions. So, option (B) is correct.