Whenever a question stem mentions an assumption or presupposition, it is a Strengthen question. We are looking for an unstated premise upon which the author's conclusion is built. We can apply the Assumption Negation Technique by making each answer choice say the opposite of what it originally said. When negated, the correct answer will contradict the conclusion.
The conclusion is that there is a lack of compassion for fellow human beings, and the evidence given is the decrease in young people interested in a medical career.
A) The author's argument is that fewer people interested in medicine = a lack of compassion. This only makes sense if having compassion leads to interest in a medical career. If we negate this answer, it says "young people with compassion for humanity will NOT pursue medical careers," which destroys the compassion/medicine link.
D) "Society as a whole" probably refers to an individual nation, so the aspirations of university students in other countries would be out of the scope of the argument. If we negate this answer, it says "the answers given in the recent poll DO NOT reflect the intentions of university students throughout the world," which has no effect on the conclusion.