I believe the answer would be A, trust yourself and you will find strength. The options B and D is out of the question due to the topic sentence being "self-reliance" and the sentence sounding firm and strong. Option C could fairly well be another answer, but to find truth, you must observe what is around you (not literally). It is A, you have to trust yourself, and when you trust yourself, you always have grand amounts of strength in yourself (confidence).
