Consider a 6-variable Boolean function f(xi, X2, X3, X4, X5, X6)=fi(X1, X2, X3, x4). f2(X4, X5, X6) where fi(x1, x2, X3, x4) = E(0,4,6,8,9,10,11,13,15) - Xi is the most significant bit and f2(x4, X5, X6) = 2(0,1,2) - x4 is the most significant bit. a) Obtain a minimal sum-of-product (SOP) expression for fi and f2 with minimum literal counts. b) Obtain a minimal product-of-sum (POS) expression for f with a minimum literal count