Question

Which scientist encouraged Frankenstein to pursue the study of natural sciences, which he had previously abandoned?

Answer 1

It is destiny that causes him to meet M. Waldman, who develops Victor's passion for the natural sciences of galvanism, electromagnetism, and alchemy.  Victor might have been a good mathematician, if he were devoid of passion.  But his passion causes him to pursue his dreams and the God-like ideal, and so he seeks intuitively to seek the answers to stopping death through the life sciences.
So yeah the answer would be the D. Waldman.