At One Time, Sea Lions Were Depleting the Stock of Steelhead

At one time, sea lions were depleting the stock of steelhead trout. One idea to scare sea lions away from the Washington coast was to launch fake killer whales, which are predators of sea lions. The cost of making the first whale is $16,000 ($5,000 for materials and $11,000 for the mold) . The mold can be reused to make additional whales, and so additional whales cost $5,000 each. Based on these numbers, the production of fake killer whales exhibits:

A) diminishing marginal product.
B) constant returns to scale.
C) increasing returns to scale.
D) decreasing returns to scale.