Electronics and Communication Engineering - Digital Electronics - Discussion

I think in any condition the 1st bit indicates sign of that number and 0 indicates positive sign and 1 indicates negative sign.

A = 11100101.
Therefore A = 00011010 and A' = A + 1 = 00011011 = 16 + 8 + 2 + 1 = 27.
Therefore A = -27.

The Answers Should be C.

Negative signed indicates the signed Binary numbers as we take compliment of only -ve signed numbers.

In any question or statement, if it is stated that it's a 2's complement, then it's obvious that the MSB is a sign bit, 0 for a positive and 1 for a negative number. In 2's complement form, if any number starts from 1, then it's a negative number, which is the case here.
So, for calculating the magnitude of the 2's-complement number, we have to take the 2's complement of the given 2's complement itself, and that will give us the magnitude only, not the sign.
The sign will be the original sign, which was before calculating the magnitude, so here the magnitude is 27, but the sign is negative.
The answer comes as -27.