Answer:
The correct answer is letter "C": Work experience.
Explanation:
People's work experience allows them to obtain knowledge in the fields they developed their careers in. There are many cases in which individuals start working n large entities to have an idea of how certain business is handled to then start their own companies confident that the knowledge acquired will be enough to run the organization.
In John's case, thanks to the complaints he heard while he was acquiring work experience in a tractor manufacturing company, he was able to open his own business to resolve the common issues he was already aware of.
