SAT English Practice Question

The novel's protagonist, a brilliant but troubled scientist, is obsessed with finding a way to reverse the aging process. His research, however, leads him down a dark path, filled with ethical dilemmas and unforeseen consequences. The scientist's obsession ultimately consumes him, leaving him isolated and alone.

1. A.leaving him isolated and alone.
2. B., leaving him isolated and alone.
3. C.; leaving him isolated and alone.
4. D.—leaving him isolated and alone.