Many explanations have been proposed for why dinosaurs became extinct. For exa
mple, some have blamed dinosaur extinction on the development of flowering pla
nts, which were supposedly more difficult to digest and could have cost consti
pation or indigestion

我個人看法是--題目是問flowering plant evolved，文章中出現在except後，代表跟前面論點相反，講的是恐龍能夠消化這些flowering plant了，所以是對前面解釋恐龍絕種的論點提出疑問

恩 感謝解惑

態度解題，(A) 是一面倒，(B) 是兩邊拔河，文章有前後對比及疑惑，選 (B)