Fast Adders of size B = 2N: Determine a function of N, that describes the cost of Brent-Kung Block Look-Ahead network. Determine a function of N, that describes the delay of Brent-Kung Block Look-Ahead network. a) b) Gate Delay Rules: All gates have a propagation delay of 1 ns independent of their size. Gate Cost rules: AND, OR and XOR all cost (1+n) where n is the number of input bits. Bubbles are free.