Which Statement BEST Illustrates Increasing Opportunity Costs

Which statement BEST illustrates increasing opportunity costs?

A) As new technology evolves, it becomes more difficult to obtain the energy to run the technology.
B) Immigration increases the productivity of the labor force even if it costs existing workers their jobs.
C) The costs of closing factories exceed the profit opportunities of keeping them operating.
D) As more rice is produced, rice farmers plant in land that is good for growing other crops but poor for growing rice.