Final answer:
A gigabyte is approximately 1 billion bytes, where one million bytes constitute a megabyte.
Therefore, the correct answer is: option c. billion
Step-by-step explanation:
In terms of multiplicative prefixes used in computer memory, the unit for one million bytes is called a megabyte (MB).
A gigabyte is approximately 1 billion bytes. Computer storage space is commonly measured in bytes with these prefixes, where one gigabyte (GB) is 1024 megabytes (MB), one MB is 1024 kilobytes (KB), and one KB is approximately 1024 bytes.
Computer storage can also be defined by larger units such as terabytes (TB), where one TB is 1024 GB.