1. "Kindly inquire further with the driver." This is the most grammatically correct and polite option. It clearly states the action you want taken and uses proper prepositions.
2. "Could you kindly inquire further with the driver?" This is a more formal way to make a request. It uses a polite conditional ("could you") and adds clarity to the request.
3. "Please inquire further with the driver." This is a direct and straightforward way to make a request. It uses the imperative form ("please") and clarifies who the inquiry should be directed towards.
4. "I would appreciate it if you could kindly inquire further with the driver." This is a more formal and polite way to make a request, emphasizing your appreciation for their help.
The best option depends on the specific context and your desired level of formality.