खालीलपैकी कोणता संच सह-मूळ संख्या तयार करतो ते शोधा.

Co-prime numbers have HCF 1. HCF(12, 7) = 1, while 21 and 42 share 21, 3 and 9 share 3, and 43 and 129 share 43 (129 = 3 × 43).