2’s-complement addition behavior: An overflow condition can occur when adding two signed numbers if both operands have the same sign; it is typically indicated by an incorrect sign bit (overflow flag). Complete the statement correctly.

Introduction / Context:
Overflow in signed 2’s-complement arithmetic occurs when the mathematical result lies outside the representable range. Recognizing the operand sign pattern that produces overflow is key for reliable ALU and software behavior.

Given Data / Assumptions:

• Operands are signed 2’s-complement numbers with the same width.
• We examine addition, not subtraction.
• Overflow flag reflects signed-range violation, distinct from carry-out.

Concept / Approach:
If two positives yield a negative, or two negatives yield a positive, overflow has occurred. Equivalently, overflow = (carry into MSB) XOR (carry out of MSB). This differs from unsigned arithmetic, where carry-out indicates out-of-range without sign semantics.

Step-by-Step Solution:

Verification / Alternative check:
Truth tables over MSB combinations and the carry-in/carry-out relation confirm the same-sign rule and the XOR overflow test.

Why Other Options Are Wrong:

• Option A/D: Use vague “error/polarity” language and do not identify overflow precisely.
• Option C: Mixes terms incorrectly and does not specify the same-sign requirement.

Common Pitfalls:
Confusing overflow with carry-out; assuming different-sign addition can overflow (it cannot in 2’s complement).

Final Answer:
overflow, both numbers, sign, incorrect sign bit