If the economy is at point c, what is the (oppurtunity) cost of 2 more automobiles?

Alrighty, I don't know what point C is but I do know what opportunity cost is and will attempt to give you some more insight into the question. Opportunity cost is a trade off. It's what you give up in order to obtain something else. For example, you would pay more in order to have a car with more safety features. A higher price for the consumers in exchange for more safety.

Bob: coke is baby pandas.jim: what? how do you figure that coke is baby pandas? bob: because this book says so.jim: how do we know the book is correct? bob: because it says that coke is baby pandas.jim: how does that prove the book's accuracy? bob: because it's statement involving coke and baby pandas is correct, therefore it is accurate.jim: how do we know that it's correct? bob: because we have concluded that the book is accurate, and therefore the statement is correct.therefore, coke is baby pandas.