What system do we use to figure out what bits our computer can use?

The correct answer is the binary system. Computers operate on a binary system because it is fundamental to their architecture and design. This system uses two states: 0 and 1, which directly correspond to the off and on states of a computer's electrical circuits. Each bit in a binary system represents a single unit of data, and combinations of these bits can represent larger values, characters, and instructions through sequences such as bytes.

The binary system is crucial in understanding how computers process information, as it forms the basis for all data representation in computing. For example, the value of each digit in a binary number is based on powers of 2, contrasting with the decimal system, which is based on powers of 10. Understanding this distinction is integral to grasping how computers store and manipulate data at a low level.

While the hexadecimal and octal systems may be used in computing for ease of representation and human readability—often serving as shorthand for binary—they are not the foundational system that determines how bits are utilized in computer operations. The decimal system is the most familiar to humans but does not apply to the internal workings of computer systems. Therefore, the binary system is the correct choice for understanding what bits our computer can use.