The correct answer is: The use of parallel plots increases tension.
This is because the simultaneous exploration of two different outcomes for the character's major life decision allows the author to create suspense and uncertainty. As the reader witnesses the consequences of both choices, it heightens the emotional stakes and investment in the character's ultimate decision. The tension builds as the character navigates the upsides and downsides of each path, leading to an anticipation of which reality they will ultimately choose to return to.