The addition and subtraction operations can be combined into one  circuit with ____________a.two common binary adder by including 2 exclusive-OR  gate with each full adderb.three common binary adder by including an exclusive-OR  gate with each full adderc.one common binary adder by including 2 exclusive-OR  gate with each full adderd.one common binary adder by including an exclusive-OR  gate with each full adder

The correct answer is d. One common binary adder by including an exclusive-OR gate with each full adder.

Here's why:

In digital circuits, an adder-subtractor is a circuit that is capable of adding or subtracting numbers (in particular, binary). Below is a simple implementation of a 1-bit adder-subtractor:

1. An XOR gate (exclusive OR) is used to add the two input bits.
2. An AND gate is used to calculate the carry-out.
3. The carry-out from the AND gate and the sum from the XOR gate are fed into an OR gate to produce the final sum.
4. The subtraction operation can be carried out by taking the 2's complement of the number to be subtracted, which is equivalent to inverting the bits of the number and adding 1. This can be achieved by using an XOR gate.

So, the addition and subtraction operations can be combined into one circuit with one common binary adder by including an exclusive-OR gate with each full adder.