Final answer:
The sentence punctuated correctly is option D, which correctly places a comma before the coordinating conjunction 'for' to separate two independent clauses. This follows the punctuation rule for joining independent clauses with a coordinating conjunction.
Step-by-step explanation:
The correct punctuation for the sentence you provided is D. I prefer to ride a bike to work, for riding a bike is a healthier way to travel. The comma before 'for' is necessary because it precedes a coordinating conjunction that connects two independent clauses. Independent clauses are sentences that can stand alone, and when they are joined by a conjunction like 'for', a comma should be used to separate them.
Example sentences from the review questions would be punctuated as follows:
- I finally found my keys, and I got to work just in time.
- Mrs. Contreras threw out her old coffee table and cleaned the carpet.
- Taking the elevator to the roof, we hoped we could see the skyline and the bay.
- Though Susan wasn't feeling well, she went to the store anyway and bought ice cream, pizza, and candy.
- I let my neighbor borrow my phone because she said hers was tapped by the police.