Vertical dashed line in graphical representation of cost function represents the

Option A is incorrect because the vertical dashed line does not represent the cost representation. The cost representation is the entire graph, not just the vertical dashed line.

Option B is incorrect because the vertical dashed line does not represent the irrelevant range. The irrelevant range is the range of activity outside of which the cost is not relevant to decision-making.

Option D is incorrect because the vertical dashed line does not represent the graphical representation. The graphical representation is the entire graph, not just the vertical dashed line.