If you go to your account, click on Shop for shore excursions and click on the descriptions it will answer your question. This is one from my upcoming cruise
PRICE is per vehicle This exclusive arrangement is designed to allow you the chance to customize your time ashore and discover the most interesting sights in the comfort and privacy of your own vehicle. With your private car and the personalized attention of your driver and English-speaking guide, you will have the flexibility and independence to design your itinerary ashore according to your own interests and sightsee at your own pace. See the most famous sights or go beyond to create your own intimate connections and unique cultural encounters. The Executive Collection is recommended for the single/solo traveler, couples, family, friends, and special interest groups traveling together. It can also be an excellent choice for physically challenged guests.