In completing Wason's four-card task,participants usually ______.

A) turn over the two cards that are necessary and sufficient to test the rule
B) turn over all four cards,when only two would have been sufficient
C) turn over all four cards,when only one would have been sufficient
D) show understanding of modus ponens but neglect modus tollens

In Wason's four-card task, participants often demonstrate an understanding of modus ponens (if P then Q, P is observed, therefore Q must be true) but tend to neglect modus tollens (if P then Q, not Q is observed, therefore not P must be true). This indicates a common reasoning error where people fail to consider or properly evaluate the necessary conditions to disprove a rule.