Step 1: Understanding MRS:
MRS stands for Marginal Rate of Substitution. It is the rate at which a consumer is willing to give up some amount of one good in exchange for another good, keeping their level of satisfaction constant. MRS is typically used in the context of indifference curves.
Step 2: Analyzing the Options:
- Option (A): Marginal rate of substitution is the correct definition of MRS.
- Option (B): Marginal rate of satisfaction does not describe MRS.
- Option (C): Marginal return of substitution is not a standard economic term in this context.
- Option (D): Marginal return of satisfaction is also not the correct definition of MRS.
Step 3: Conclusion:
The correct answer is option (A), Marginal Rate of Substitution.