The number the computer system always uses to calculate and store data in ‘0’ and ‘1’ is:

A. Binary
B. Hexadecimal
C. Octal
D. Decimal
E. Heptadecimal

Answer: A. Binary

Explanation:
Computers operate using the binary number system, which is based on two values, ‘0’ and ‘1’. All data and instructions processed by computers are ultimately represented using binary digits.