6- (total 8 pts, 2 pts each) The four pictures shown below represent four cards. Each card has a letter on one side and a number on the other. For two of the cards, the letter is visible and the number is hidden. For the other two cards, the number is visible and the letter is hidden. A person claims that all the cards satisfy the following property: If the letter on one side is a vowel, then the number on the other side is even. You suspect that the person's claim may be false. In other words, you suspect that the property may fail to hold for one or more cards. (a) Do you need to turn over the card with the E to check whether the claim is false? Why or why not? (b) Do you need to turn over the card with the 7 to check whether the claim is false? Why or why not? (c) Do you need to turn over the card with the 4 to check whether the claim is false? Why or why not? (d) Do you need to turn over the card with the K to check whether the claim is false? Why or why not