Sentences with errors in parallel structure have conflicting tense and structure. Option C is correct.
Parallel structure which also known as parallelism, is the repetition of a chosen grammatical form within a sentence. By making each compared item or idea in your sentence follow the same grammatical pattern, you create a parallel construction. In a parallel structure there should not be conflinctin tense or structure. It should follow the pattern.
Gregor's feelings about his job as a traveling salesman are made clear very early in Part I of the story.
Even though Gregor despises his job, he continues to work because his parents owe Gregor's boss money. He plans to quit the miserable job when he has saved enough money to pay his parents' debt--in five or six years.
