Question 18 (3 points) Which of the following regression cost models would be the best? a) Economically plausible; t-value = 4; r2 (coefficient of determination) = 0.49 Economically plausible; t-value = 3; r2 (coefficient of determination) = 0.45 Economically plausible; t-value = 2; r2 (coefficient of determination) = 0.30 d) Economically plausible; t-value = 2; r2 (coefficient of determination) = 0.40