1) Vaccum your house weekly.
2) Don't drop food crumbs on the floor. If you do, then sweep it immediately.
3) Clean your backyard well too, remove the weeds etc.
4) Wash the floors with water & soap weekly too.
The correct answer for the question that is being presented above is this one: "A. the relationship between the elements of your thought." Parallel structure is used to make clear the relationship between the elements of your thought.
Here are the following choices:
A. the relationship between the elements of your thought
B. the high quality of your writing
C. the subordinate clause structure