Whenever the sun is shining and the windchill factor is below zero, Susan wears her parka. Whenever it is raining and the windchill factor is above zero, Susan wears her raincoat. Sometimes it rains when the sun is shining.
If the above statements are true, which of the following must also be true?
(A) If it is not raining adn Susan is wearing her parka, the sun is shining.
(B) If the windchill factor is below zero and Susan is not wearing her parka, the sun is not shining.
(c) If the windchill factor is below zero and it is not raining, Susan is wearing her parka.
(D) If the windchill factor is below zero and it is raining, Susanis wearing her raincoat.
(E) If it rains while the sun is shining and the windchill factor is zero, Susan wears her parka.
正確答案B
我自己選D 裡面蘊涵的邏輯我不懂@@