The subjunctive mood is the best.
The subjunctive is rarely used in colloquial English. Totally irrelevant information, but... it is a relic from Latin, where there are many uses for a subjunctive. There is even a special conditional using the subjunctive mood that expresses the exact circumstances you described, which is usually called future less vivid.
Answer:
A A catastrophe is any event that is unexpected
Answer:
I hope C is the best one .....
I wouldnt know.......................................
