How does the marginal rate of technical substitution (MRTS) affect input substitution?

• A. It determines the rate at which one input can be substituted for another while maintaining the same level of output.
• B. It indicates the maximum output achievable with a given set of inputs.
• C. It measures the cost efficiency of different input combinations.
• D. It shows the diminishing returns of adding more inputs.

Answer: (A)