Answer: B. An isocost curve represents all possible combinations of the inputs of production that yield the same cost.
D. The cost function measures the minimal cost of producing any level of output, given the costs of the factors of production.
E. An isoquant represents all possible combinations of the inputs of production that yield the same level of output.
Explanation:
Option A is incorrect
The conditional factor demand doesn't give the profit maximizing level given the output choices.
Option B is correct
An isocost curve represents all possible combinations of the inputs of production that yield the same cost.
Option C is incorrect
If the cost of producing y units of output is C dollars, it doesn't imply that the isoquant for the level of output y must be identical to the isocost for C dollars.
Option D is correct
The cost function measures the minimal cost of producing any level of output, given the costs of the factors of production.
Option E is correct
An isoquant represents all possible combinations of the inputs of production that yield the same level of output.
Therefore, the correct options are B, D, and E.