Answer: A. binary number system
Explanation:
A binary number system method simply has in its base the number 2. In this case, the digits used are 0 and 1. .
Octal number system, simply means the base-8 number system. In this case, the digits used are 0 to 7.
The decimal number system is the base-10 number system. In this case, it is made up of digits from 0 to 9.
The hexadecimal numeral system, consists of 16 symbols. It uses both the decimal numbers and then uses six extra symbols.
