A sign outside a restaurant reads, "If you are wearing a hat, you will be seated at the counter." Which one of these statements necessarily follows logically?
If you are not wearing a hat, you will not be seated at the counter.
If you are seated at the counter, you were wearing a hat.
If you are not seated at the counter, then you are not wearing a hat.
If you are wearing a hat, you might be seated at the counter.
You must be wearing a hat to be seated at the counter.
