1100 1100 (correct)
The number to be subtracted is negated by the usual means (reflect the bits, add one):
0101 1100 → 1010 0111
Then the "binary addition algorithm" is used:
00100 111 0010 0101 = 3710 1010 0111 = -8910 --------- ----- 1100 1100 -5210
Since the carry into the most significant column is the same as the carry out of that column the result is correct. The answer came out negative, but that is fine.
You must practice the "binary addition algorithm" until you are sick of it. Or you can change your major to Art History (and leave the high paying jobs to the rest of us). Here is another problem: