What Is Wrong with the Following Statement: "An Adaptation Is

What is wrong with the following statement: "An adaptation is a trait whose fitness benefits (B) exceed its costs
(C) ) "

A) An adaptation can have higher C than B if the trait helps the species survive.
B) The benefits associated with an adaptation must be greater than the costs, and in addition the trait must help individuals to survive.
C) The benefits associated with an adaptation must be greater than the costs, and in addition the difference between B and C must be greater than that associated with any other alternative trait.
D) The benefits associated with an adaptation must be greater than the costs, and in addition the trait must be more common than any other alternative trait in the population.