She met her friends in the lobby of the hotel, and they headed over to the pool for a cool, refreshing swim.
Explanation:
The correct option is the first one. This revision is the most concise, free of redundancy. This means that everything necessary is said with no unnecessary words. When we say that someone is in the lobby of a hotel, we already know that they are on the bottom floor. There is no need to include both <em>lobby </em>and <em>bottom floor </em>in the same sentence. The first sentence is the only one that contains only one of these phrases/words.
Another issue with the original sentence is the incorrect use of commas, and another reason the third option is incorrect is awkward word order.
