On the Classic Selection Task in Conditional Reasoning, People Work

On the classic selection task in conditional reasoning, people work on the problem, "If a card has a vowel on one side, then it has an even number on the other side." Research on variations of this task indicates that

A) people consistently seek out negative information rather than positive information.
B) the problem is easier to solve if it describes something concrete, such as drinking age.
C) this is one of the few tasks that people can solve more accurately in their heads than when the problem is represented with concrete objects.
D) people are systematically influenced by the representativeness heuristic.