How scarcity and choice related?

Answer 1

Due to scarcity, choices have to be made. Choices will be made after the opportunity cost of a decision is weighed up.

Example: you need a drink. you have just enough for one can of drink. the choice is coca cola or pepsi. You want both - because you are human - but you have scarce resources - money. You have to make a choice. You choose coke - so therefore the can of pepsi becomes your opportunity cost - its what you could have had, but because of your decision, you missed out on it.