A. The contribution margin of Department B is equal to the total revenues of Department B less total variable costs of Department B. See the correct answer for a complete explanation.

B. This answer assumes that fixed costs are also deductible. However, contribution margin is calculated as total revenues minus total variable costs.

C. The contribution margin of Department B is equal to the total revenues of Department B minus the total variable costs of Department B. See the correct answer for a complete explanation.

D. The contribution margin of Department B is equal to the total revenues of Department B less total variable costs of Department B. It is calculated as follows: $400,000 + $15,000 - $65,000 - $40,000 - $15,000 - 30,000 = $265,000.