The correct answer is C. Bit.
A bit is the most basic unit of information in computing and digital communications. It is a binary digit, meaning it can only have one of two values: 0 or 1. Bits are used to represent numbers, letters, and other symbols.
A byte is a group of 8 bits. Bytes are used to represent numbers, letters, and other symbols.
A baud is a unit of signaling speed in telecommunication equal to the number of signal elements transmitted per second.
Therefore, the only option that represents a unit of discrete information is C. Bit.