20 LDA 60 21 ADD 61 22 OUT 23 COB 60 DAT 25 61 DAT 6 Show the contents of IR, PC, MAR, IOR, and A at the conclusion of instruction 21. The register transfer language sequence has been included to help you sequence the events. PC MAR MDR IR IR[Address] -> MAR A +MDR A PC + 1 PC IR MAR IOR A PC