What bad weather ruined the trip.

Reason: Illness and bad weather ruined the trip. With=together with/with, which means that illness and bad weather ruined the trip.

Agreement A is meaningless, connection B is connected, and connection "contact" does not mean that illness "is related to bad weather". They are just two independent factors, both of which lead to the failure of travel. In addition, connect is an intransitive verb, and the object should be followed by the preposition with.

I hope it can help you learn and progress.