Decimal number system has how many digits?

Correct option is C

Ans. (c)
Sol. The decimal system is a base-10 number system, meaning it has 10 unique digits (0–9). It is the most commonly used system in everyday life, from banking to measurements. Computers internally work with the binary system (base-2), but humans use decimal by default.
Explanation of each option:
· (a) 2 – Binary system, used by computers.
· (b) 8 – Octal number system.
· (c) 10 – Correct. Digits 0 through 9 make up the decimal system.
· (d) 16 – Hexadecimal system (0–9 and A–F).