Mike's Radiator Services specializes in the repair and replacement of radiators for passenger vehicles. Variable and fixed costs related to installation activities for the most recent month (January) are listed below: 2. Mike expects that 108 radiators will be installed in February and that this level of activity is within the relevant range for all variable and fixed expenses. a&b-1. Calculate the total expense and per unit amounts for each of the variable and fixed cost items above. (Round "per unit" answers to 2 decimal places.) b-2. Explain any differences in the per unit amounts between January and February. 3. Which, if any, of the costs shown above would be considered sunk costs? Why