Step 1: Understanding isoquant curve.
An isoquant curve represents all the combinations of two inputs that produce the same level of output. It is similar to the indifference curve in consumer theory, but it applies to production, not consumption.
Step 2: Analyzing the options.
(A) Isoquant curve: Correct. An isoquant curve shows all possible combinations of two inputs that yield the same level of output.
(B) Indifference curve: This refers to a graph used in consumer theory to represent combinations of goods that give the same level of satisfaction.
(C) Isoscost curve: This refers to combinations of inputs that cost the same amount, which is not related to output levels.
(D) None of these: This is incorrect, as the correct answer is (A) Isoquant curve.
Step 3: Conclusion.
The correct answer is (A) Isoquant curve, as it represents combinations of inputs that produce the same level of output.