To drive a car with a **3,000-kilogram MMA** that is towing a trailer with an **800-kilogram MMA**, you need to consider the following:

- With a **class B driving license**, you can operate vehicles that do not exceed **3,500 kilograms** and combinations of vehicles as long as the trailer does not exceed **750 kilograms**. In this case, the trailer weighs more than 750 kilograms, so the B license alone is not sufficient.

- To drive this combination of vehicles, you need an **additional authorization**. This authorization is the **B+E license**, which allows you to operate combinations of vehicles where the trailer can carry a load of up to **3,500 kilograms**.

Therefore, the correct answer is that you can drive the car and the trailer, **as long as you have an additional authorization** such as the B+E license.