Answer: Positive economics
Explanation: The benevolent social planner is an imaginary figure who is omniscient and has good intentions towards the people in a society. The goal of this planner is to maximize the economic welfare of people, achieve economic efficiency in the market and distribute income fairly. He does this by looking at historical and current economic data such as consumer and producer surplus. This type of economics practiced by this planner is the positive economics.
Positive economics studies current and past economic activity to make predictions about the future.
The benevolent social planner is only a hypothetical figure who serves as a reference for economic policy makers.