The correct answer is C. All the telephone wires have been cut.
A. All the telephone wires will be cut is in the future tense, which does not match the context of the sentence. The sentence is about something that has already happened, so the future tense is not appropriate.
B. All the telephone wires had been cut is in the past perfect tense, which can be used to talk about something that happened before another event in the past. However, the sentence does not specify any other event that happened before the telephone wires were cut. Therefore, the past perfect tense is not necessary.
D. All the telephone wires shall be cut is in the imperative mood, which is used to give commands or make requests. However, the sentence is not a command or a request. It is a statement of fact. Therefore, the imperative mood is not appropriate.
In conclusion, the correct answer is C. All the telephone wires have been cut.