Which of the following statements about representations is true?

• A. Binary uses base 2 (0/1), decimal uses base 10; hexadecimal uses base 8.
• B. Binary uses base 2; decimal uses base 12; hexadecimal uses base 16; conversions between them are common.
• C. Binary uses base 16; decimal uses base 10; hexadecimal uses base 2.
• D. Binary uses base 2 (0/1), decimal uses base 10; hexadecimal uses base 16; conversions between them are common.

Answer: (D)

Number bases describe how we encode values. In computing, binary is base 2, using digits 0 and 1. Decimal is base 10, using digits 0 through 9. Hexadecimal is base 16, using digits 0–9 and letters A–F to represent 10–15. Because these bases are used in different aspects of computing, converting between them is common—binary data is often shown in hex for readability, and hex provides a compact way to represent long binary values. This makes the statement true: it correctly pairs the bases with their standard digits and notes that conversions between them are common. The other ideas aren’t correct, such as decimal being base 12 or hexadecimal being base 2, which don’t match how these representations are actually used.