Several Studies Have Shown That Attitudes Are Only Mediocre Predictors

Several studies have shown that attitudes are only mediocre predictors of behaviour.What is an explanation for this finding

A)  Researchers failed to operationalize the concept of an attitude. 
B)  General beliefs and feelings aren't likely to predict specific behaviours very well. 
C)  Researchers failed to take variations in attitude strength into account. 
D)  Subjects often intentionally lie about both their attitudes and their behaviour.