Answer:
Increase in the price level.
Explanation:
A decline in the quantity of real output demanded along the aggregate demand curve is a result of an increase in the price level.
This ultimately implies that, an increase in the price level of a product usually results in a decrease in the quality of real output demanded along the aggregate demand curve.
According to the law of demand which states that, there exist a negative relationship between the quantity of goods demanded and the price of a good. This simply means that, when the prices of goods and services in the market increases or rises: there would be a significant decline or fall in the demand for this goods and services.