Which of the Following Reasons, Explaining the Difficulty of Reporting

Which of the following reasons, explaining the difficulty of reporting, is unique to environmental and social impacts? (In other words, which of the explanations is an issue relating to environmental and social costs, but does not relate to other costing issues faced by firms?)

A) Future ecological and social issues are not yet known.
B) Many costs and benefits are external (they occur outside the organisation) .
C) Many costs and benefits are difficult to quantify.
D) None of the given answers