The correct answer is C) Either I or II. If a circuit breaker that utilizes built-in, current limiting fuses (CLFs) cannot be closed or reset, the problem could be either a blown current limiting fuse due to a short-circuit condition (option I) or a missing current limiting fuse (option II). Both scenarios would prevent the circuit breaker from being closed or reset, as the CLFs are an integral part of the circuit breaker's operation. The other options are incorrect because: A) is too specific, as either a blown fuse or a missing fuse could cause the issue; B) is incorrect, as a missing fuse would also prevent the circuit breaker from functioning properly; and D) is incorrect, as one of the two options presented is the likely cause of the problem.