Which phrase indicates that someone is unable to copy a message due to being engaged in current tasks?

The phrase "busy" appropriately conveys that an individual is currently occupied with other tasks or responsibilities, preventing them from being able to copy or respond to a message at that moment. This term is commonly used in communication contexts to indicate that someone is engaged in other activities, making it clear that they cannot take the time to process additional information until they are free.

The other options do not capture this specific context as accurately. "In service" typically refers to being available and active in providing service, while "out of service" indicates a state where someone or something is unavailable for use or communication altogether. "Receiving well" suggests that the person is in a good position to receive messages but does not imply that they are busy with existing tasks. Therefore, it is clear that "busy" is the most fitting description of someone who cannot copy a message due to current engagements.