Binary Number System Identification

The binary number system, also known as base-2, is a way of representing numbers using only two digits: 0 and 1.

Analyzing Options for Binary Representation

We need to examine each option to see if it exclusively uses the digits 0 and 1.

• Option 1 (9): This number includes the digit '9'. Binary numbers only use '0' and '1'.
• Option 2 (89056): This number contains digits like '8', '9', '5', and '6', which are not part of the binary system.
• Option 3 (100101): This sequence is composed solely of '1's and '0's. It is a valid binary number.
• Option 4 (ABCDE): This option consists of letters, not digits, and therefore does not represent a number in any standard positional numeral system, including binary.

Determining the Binary Example

Only the number 100101 meets the criteria of the binary number system by using only the digits 0 and 1.