A parallel (ripple-carry) adder consist of N full adders chained together. The carry out of one stage acts as the carry in of the next stage as shown in Figure 3 below. A carry-lookahead adder (CLA) divides the adder into blocks and provides circuitry to quickly determine the carry out of a block as soon as the carry in is known. Thus it is said to look ahead across blocks rather than waiting to ripple through all the full adders inside a block. An example is shown in Figure 4 below. When would a digital circuit designer choose a parallel (ripple-carry adder) over a carry-lookahead adder? 0 Cy Full Co Adder 0 Full 3 Full Adder1 iAdder 0 . end-around carry for 1's complement Figure 3