The correct answer is: D. Both A & B
A number system is a system for representing numbers using digits. The essential features of a number system are:
- Radix: The radix, also called the base, is the number of unique digits that are used to represent numbers in the system. For example, the decimal number system has a radix of 10, which means that it uses the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.
- Set of distinct counting digits: The set of distinct counting digits is the set of digits that are used to represent numbers in the system. For example, the decimal number system has the set of distinct counting digits {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}.
The radix and the set of distinct counting digits are the two essential features of a number system. Without these two features, it would not be possible to represent numbers in the system.
Option A: Radix
The radix is the number of unique digits that are used to represent numbers in the system. For example, the decimal number system has a radix of 10, which means that it uses the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.
Option B: Set of distinct counting digits
The set of distinct counting digits is the set of digits that are used to represent numbers in the system. For example, the decimal number system has the set of distinct counting digits {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}.
Option C: bits
Bits are the basic units of information in computing and digital communications. A bit is a binary digit, which can be either 0 or 1. Bits are used to represent numbers, letters, and other symbols.
Option E: None of the above
Option E is not a correct answer because it does not include both the radix and the set of distinct counting digits.