You are given a program that includes a method M that executes sequentially. Use Amdahl's Law to resolve the following questions: $($a$)$ Suppose M accounts for $50\%$ of the program's execution time. What is the limit for the overall specdup that can be achicved by running the program on an n$-$processor machinc $?($b$)$ Suppose M accounts for $80\%$ of the program's execution tine. You hire a programmer to repluce M with M$\text{'},$ which holds k $-$ fold specdup over M$.$ What value of k yiclds an overall specdup of $5$ for the whole program $?.$