PLEASE HELP ME
How would you tell a group of people to prepare for a hurricane?
A. Preparan para un huracan.
B. Prepara para un huracan.
C. Preparense para un huracan.
D. Prepare para un huracan.
I am almost for sure you need to use the imperative form of the verb preparar but I can't decide between B and D. I still have a bit of trouble choosing ustedes vs tu for the verb. Help would be appreciated.