Apart from philosophical and legal reasons for respecting patients' wishes, there are several practical reasons why doctors should________to involve patients in their medical care decisions.
本题考查词义辨析。
题目意为“除了尊重病人意愿的伦理和法律原因外，之所以说医生应该努力让病人参与他们的医疗决策还有几个实际原因。”A选项“提高，巩固”，B选项“执行，支持”，C选项“努力，尽力”，D选项“资助，捐赠”。endeavor to do sth. 努力做某事，其它几个选项后面都接名词（或代词）作宾语，一般不用动词不定式。C选项符合题意。
故正确答案为C。