Realize the function f(a,b,c,d,e) = Σm(6,7,9,11,12,13,16,17,18,20,21,23,25,28) using a 16-to-1 MUX with control inputs b,c,d, and e. Each data input should be 0,1,a, or a'. Hint: Start with a minterm expansion of F and combine minterms to eliminate a and a' where possible.