4. You are working for a company that is trying to decide whether to implement a ripple-carry adder (Q1b) or a carry-lookahead adder (Q3a). You need to present a report, which includes two parts. You may include a suggestion at the end to help the management decide. a) How many times gates are needed in the carry-lookahead adder compared to the ripple- carry adder? (10) b) What is the speed up of the carry-lookahead adder compared to the ripple-carry adder? To do this, you need to find the total delay of the critical path (first input to final carry out) of both the adders. You can assume an average gate delay of 10 ns. (15) Hint: If circuit A requires half the time as circuit B, the speedup of circuit A to circuit B is

Fig: 1