Cho has opened a new startup company in web design. within the first month of business, the startup agrees to maintain an accounting firm's website in exchange for someone doing their tax returns.

The question is not complete, last part of the question is missing which I write below;

Which of the following principles of economic interaction best describes this scenario?

And the answer is "trade can make everyone better off ".

Trade can make everyone better off in light of the fact that it enables nations or companies to work in what they excel at and to appreciate a more extensive assortment of products and ventures.

The three principles concerning economic interactions are:

(1) Trade can make everyone better off;

(2) Markets are generally a better way to arrange economic activity

(3) Governments can at times develop market outcomes.