I am confused between the two costs, opportunity cost and relevant cost. What's the relation between them and difference from each ? Can someone help to explain it? Thx.

I am confused between the two costs, opportunity cost and relevant cost. What's the relation between them and difference from each ? Can someone help to explain it? Thx.
Answer please !

An opportunity cost is one which measures the cost of sacrificing one course of action in favour of another. If I play a video game rather mowing someone's lawn for a fee, the opportunity cost of the video game is the fee I chose not to earn.

A relevant cost or benefit is one that will be affected by the decision. Overhead is not relevant because it is incurred whether you make the decision or not.