Style guide for time formats

Style guide for time 

1. The event is from 5 p.m. to 7 p.m. in the Green Library.
2. The event is from 5p to 7p in the Green Library.
3. The event is from 5 pm to 7 pm in the Green Library.
4. The event is from 5pm to 7pm in the Green Library.
5. The event is from 5PM to 7PM in the Green Library.