A bit.
If you are asking what is four (4) in the binary system, the answer is 100.
15
1100
The weight of the Most Significant Bit (MSB) in a 5-bit binary number is 16. In binary representation, each bit position corresponds to a power of 2, starting from the right with 2^0. Therefore, the MSB, which is the leftmost bit in a 5-bit number, represents 2^4 or 16 in decimal.