Which usage sparked the oil search? heating the home lighting large cities fueling engines making other products

Option C.

Explanation:

Fueling engines, is the right answer.

The oil industry has remained a significant industry, in the history of the world. This industry played an important role in the development of various industries throughout the Industrial Revolution period. This was the period when for the very first time, machines were used to produce goods on a large scale. The fueling engines required fuel to run thus it sparked the oil search.

Firstly he should have educated the workers on how to maintain the machines to begin with, yet if it's out of their hands and a machine broke down he should try talking them through fixing if it's simple - and if it's something either extremely technical or dangerous John should replace or repair the machines via a technician (someone who knows how the machines work).
Depending on the machine a technician may be the first course of action, over all else.