Correct : a,c

The correct answers are Option A (Z = X − Y) and Option C (Z = −X + Y).
First, let''s decode the two signed magnitude numbers. In signed magnitude, the MSB is the sign bit (1=negative, 0=positive) and the remaining 7 bits give the magnitude.
X = 10110100: Sign = 1 (negative), magnitude = 0110100₂ = 52. So X = −52.
Y = 01001100: Sign = 0 (positive), magnitude = 1001100₂ = 76. So Y = +76.
For 8-bit signed magnitude, the valid range is −127 to +127 (7 bits for magnitude, max = 127). Any result with magnitude > 127 causes overflow.
Now evaluate each operation:
Option A — Z = X − Y = −52 − 76 = −128: Magnitude = 128 > 127 → Overflow ✓
Option B — Z = X + Y = −52 + 76 = +24: Magnitude = 24 ≤ 127 → No overflow
Option C — Z = −X + Y = +52 + 76 = +128: Magnitude = 128 > 127 → Overflow ✓
Option D — Z = −X − Y = +52 − 76 = −24: Magnitude = 24 ≤ 127 → No overflow
Both A and C produce a result of magnitude 128, which exceeds the 7-bit magnitude limit of 127, causing overflow in signed magnitude representation.