Mark is an excellent cook. he does not have any formal training but learned to cook by following the recipes of several famous chefs and his mom. every weekend, he invites friends over for dinner so he can try new dishes and get honest feedback from his friends. mark wants to start his own restaurant someday because he thinks he would be successful and become wealthy. which of adam smith’s ideas made mark think of starting a restaurant?
invisible hand
self-interest
competition
laissez-faire

The answer is "self-interest".

Self-interest is characterized as being centered around yourself or putting yourself at leeway.  

An example of Self-interest is pondering your necessities over the requirements of others around you.  

Self-interest is when people settle on choices that are in their very own best advantage. Like when you choose to get up early in the day to go to work and profit, or when you pay the supermarket for sustenance that you might want to eat.

two years ago, when picking flowers in the mountains back of yosemite valley, i found a book. it was blotted and storm-beaten; all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however; many of the inner pages were well preserved. and although all were more or less stained and torn, whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today; its granite pages have been torn and blurred by the same storms that wasted the castaway book.

two years ago, when picking flowers in the mountains back of yosemite valley; i found a book. it was blotted and storm-beaten, all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however, many of the inner pages were well preserved. and although all were more or less stained and torn; whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today, its granite pages have been torn and blurred by the same storms that wasted the castaway book.