The Danger in Using Data to Estimate the Consequences of a Proposed

The danger in using data to estimate the consequences of a proposed policy is that ________.

A) the data can reveal only the benefits of a policy,while estimating the policy's costs is important,also
B) policies change so often that data can never reveal which policies are the cause of which consequences
C) the public's expectations about the policy might influence the data,making the policy seem more or less appropriate than is actually the case
D) the proposed policy,if implemented,might cause unforeseeable changes in the relationships that were in operation when the data were produced