In a carry look ahead adder,the carry signals are generated in advance based on input signals,two four bit no. are to be added like
A3 A2 A1 A0
+ B3 B2 B1 B0
......................................
all the no.s are available in the beginning,C0 is the initial carry and C4 is the carry from MSB i.e final carry.To calculate the final signal C4,how many gate levels are required?assume only basic gates are (AND ,OR,NOT)are available.