Answer:
A. real GDP; real GDP; AD; SAS
Explanation:
When we speak about equilibrium in economics, we are mentioning that something is equal to something, in this case, the demand equals the supply. When we speak about macroeconomic equilibrium, we are saying that the Aggregate Demand (AD) is equal to the Short-run Aggregate Supply (SAS). This means that both quantities are the same, namely the quantity of real GDP demanded is equal to the quantity of real GDP supplied. In the graph, we see that both curve meet (i.e. the point of intersection).