In 16-bit 2's complement representation, the decimal number $-28$ is:

To represent $-28$ in 16-bit 2's complement:

1. Find the 16-bit binary representation of $+28$:

   $$+28 = (0000\ 0000\ 0001\ 1100)_2$$

2. Compute its 1's complement (invert all bits):

   $$1111\ 1111\ 1110\ 0011$$

3. Add $1$ to get the 2's complement:

   $$1111\ 1111\ 1110\ 0011 + 1 = 1111\ 1111\ 1110\ 0100$$

This matches option (C).