Can I eliminate the question on Schedule C, I did not use my car for business and do not understand what 'less than 5 at a time mean

If you do not use your vehicle for business purposes and are not claiming mileage you can skip the question.  

For most people, the answer to the question 'Did you use less than 5 vehicles for business at a time' will be 'Yes'.  As a sole-proprietor using your own vehicle for business purposes, your answer would be 'yes'.
 

An example for when the answer would be 'no' is a business that owns 5 work trucks and has employees who use the trucks on a daily basis.  This business will be restricted with whether they can use the standard mileage rate for all 5 work trucks. 
 

Try to delete the Car & Truck Expenses Worksheet in TurboTax Online

1.       Open your return in TurboTax. ...

2.       In the upper right corner, click My Account > Tools.

3.       In the pop-up window, select Delete a form.

4.       Click Delete next to Schedule C (Contractor) -- Car & Truck Expenses Worksheet and follow the onscreen instructions.
 

Click here for additional information on Business use of car.