Final answer:
A binary digit in computing is referred to as a 'bit'. It's the smallest unit of data, with larger units such as kilobytes, megabytes, gigabytes, and terabytes representing multiples of 1024 bits.
Step-by-step explanation:
Computers operate using a binary machine language that interprets data through sequences of binary ones and zeros. Each of these binary digits is known as a bit. A bit is the smallest unit of data in a computer and represents a single binary value, either 0 or 1.
To clarify further, larger data measures include the kilobyte (KB), megabyte (MB), gigabyte (GB), and terabyte (TB), with each subsequent unit being a multiple of 1024 of the previous one. For example, 1 KB is approximately 1000 bytes (technically, 1024 bytes), 1 MB is 1024 KB, 1 GB is 1024 MB, and 1 TB is 1024 GB.
Therefore, when referring to a binary digit in the context of computer data, the correct answer is 'a. bit'.