2. A full-adder can be implemented with: a. Two 2 x 4 decoders with enables b. One 3 x 8 decoder with no enable c. Two half-adders . d. All of the above 3. Assume that A and B are 4-bit numbers. The following circuit can be used to: A B D D +D Az B2 Az . a. Compare if the numbers A and B are equal b. Multiply A and B c. Add A and B d. None of the above