The Excess-3(XS3) code for a given decimal number is determined by adding '3' to each decimal digit in the given number and then replacing each digit of the newly found decimal number by its four bit binary equivalent. The table gives is the Excess-3 code. For example, XS3 code of 24 is obtained as
Thus, XS3 code of 24 is 0101 0111.
The key feature of the Excess-3 code is .that it is self complementing. In other words, the 1's complement of an Excess- 3 number is the Excess- 3 code for the 9's complement of the corresponding decimal number.
For example, the Excess- 3 code for decimal 6 is 1001. The 1's complement of 1001 is 0110, which is the Excess-3 code for decimal 3, and 3 is the 9's complement of 6. This property of Excess-3 code makes it useful in some arithmetic operations.
Hence,Option(C)Self-complimenting Code is the correct choice.