Binary Coded Decimal uses groups of four bits to represent decimal numbers.

• A. A system of representing binary numbers with six bits
• B. A type of decimal encoding with eight bits per digit
• C. A floating-point representation
• D. A numbering system using four-bit groups to represent decimal digits

Answer: (D)

Binary Coded Decimal represents each decimal digit separately, using a four-bit pattern for every digit. Each digit from 0 to 9 has its own 4-bit code from 0000 to 1001, so a multi-digit number is written as adjacent four-bit groups. For example, the decimal 93 becomes 1001 0011, with a four-bit group for the 9 and another for the 3. This encoding keeps decimal digits intact for easy display and decimal arithmetic, unlike pure binary or floating-point representations. The other descriptions don’t match this scheme: there isn’t a six-bit binary system, there isn’t eight bits per digit, and it isn’t a floating-point format.