What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? William is rich if and only if it is overcast. If Mary drinks water, then it is cold. It is overcast or it is windy. If it is windy, then William is rich. If William were rich, then Mary is drinking water. If it is cold, then Thomas is playing tennis.
If Mary drinks water, then Thomas is playing tennis. If it is windy, then Mary is drinking water. If William were rich, then it is cold. If William were rich, then it is overcast. If it is overcast, then William is rich.