Answer: When total surplus gets maximized, then economy meet economic efficiency.
Explanation:
Economic efficiency is described as a thinking that there is one possible way to make situation better by imposing a cost on another.
Total surplus is described as the sum of producer and consumer surplus.
It gets maximized in a perfect competition (hit free-market equilibrium).
i.e. It gets maximized when both consumer and producer surplus is maximum, and then the economy meet economic efficiency.
