What Is a Potential Problem with Entering into a "Lubrication

What is a potential problem with entering into a "Lubrication, Inspection, and Small Parts"contract for newer elevator equipment?

A) These contracts don't usually include any trouble calls.
B) A newer elevator will probably not have many "small parts" that will be covered, leading to unexpectedly high repair costs.
C) The customer receives less comprehensive service than in a Lubrication & Inspection contract.
D) All of the above