請英文好的人幫我分析一下 - 社會議題

最近在準備考試、做考古題，遇到不清楚的題目麻煩英文好手幫我解答：
1. Finding the magic formula for success has long been an _____ goal.
(A) inclusive
(B) elusive
(C) patient
(D) invasive
2. Global warming ______ images of rising seas that threaten coastal areas.
(A) conjures
(B) excites
3. Pet therapy _____ to help people with depression, Alzheimer's disease, and other mental conditions.
(A) proved
(B) has proven
(C) has been proven
(D) is proving
4. The ____ of water has become a source of global tension ecologically, economically and politically.
(A) scarcity
(B) abundance
謝謝!!!!