12. What flag is set if the following calculation is done with signed numbers represented in 4-bit twos complement representation? -6-5 A. carry C. none B. overflow D. both carry and overflow 13. What flag is set if the following calculation is done with unsigned 4-bit numbers? 9 7 A. carry C. none B. overflow D. both carry and overflow 14. In the number 509832, the 5 is referred to as the A. most significant digit C. radix B. least significant digit D. base 15. What is the difference of the following two numbers in 8-bits using two's complement arithmetic? 11010100 10000111 A. 10100110 C. 01001101 B. 01111001 D. 10010011 16. What flags are set when the above operation is performed? A. carry B. overflow C. none