How many inputs does a full-adder circuit have for each individual binary…

Concept: A binary adder circuit is classified by how many single-bit inputs it accepts at each bit position. A Half Adder is the simplest adder: it takes exactly two inputs, the two bits being added, and produces only a Sum and a Carry-out, with no way to accept an incoming carry. A Full Adder extends this by adding a third input, the Carry-in, so it can be chained across bit positions (a ripple-carry adder) to add, or, using 2's complement, subtract multi-bit binary numbers.

Application: For each bit position that a full adder processes, it needs:

• Input 1 -- operand bit A at that position

• Input 2 -- operand bit B at that position

• Input 3 -- the Carry-in received from the previous (less significant) position

These three binary inputs are combined to produce a Sum output for that position and a Carry-out, which then becomes the carry-in for the next position. So a full-adder circuit has three inputs for each individual binary digit being added or subtracted.

Cross-check: This is confirmed by contrasting with the other adder-related option value offered:

• 2 inputs describes a Half Adder (only A and B, no carry-in) -- used solely at the least-significant bit position, where there is nothing to carry in from.

• 4 inputs would need a second carry line or an extra operand that a basic full-adder cell does not have; only one carry-in signal is required per stage.

Hence the full adder's input count for each digit position is 3.