The correct answer is - a supply curve and a demand curve meet.
An equilibrium, from an economical perspective, in essence means that the supply and demand for a product or service are equal.
This would basically mean that the amount that is produced of some good is the totally same amount that is demanded and all of it will be sold, without having any surplus, or be lacking in quantity.
The price in an equilibrium situation is defined by the point in which the supply and demand curves intersect.
