Green Woods sells specialty equipment for mountain climbers. Its sales for last year included $238,000 of tents and $411,000 of climbing gear. For next year, management has decided to sell specialty sleeping bags also. As a result of this change, sales projections for next year are $264,000 of tents, $426,000 of climbing gear, and $51,000 of sleeping bags. How much of next year's sales are derived from the side effects of adding the new product to its sales offerings? a. $0 b. $20,500 c. $41,000 d. $51,000 e. $82,000