Correct option is D
This is unrelated to billing errors. It's about power supply, not billing.
So, it is not a logical effect of the given cause.
Effect II: The municipal commissioner clarified that a technical glitch caused the billing issue and would be fixed in 48 hours. → Possible
This is directly related to the cause. It addresses the billing problem.
Effect III: Long queues were seen outside electricity board offices. → Possible
This is also very likely, as people may rush to complain or clarify their bills.
Thus, the correct option is (d) Both II and III are possible effects.