Either Mark or his students were on the ferry boat.
They can investigate about the topic being persuaded about throughout multiple different sources, they can not act on a whim and be like hey that sounds cool lets do it.
Since a participle takes the form: verb + -ing, the only word in this sentence which has such a form is B, 'challenging'. 'Puzzle' is a noun, 'crossword' is an adjective, 'created' is a verb.
Answer:
<em>Parents.</em>
Explanation:
Seat belts provide the best protection for passengers in a car. This advertisement emphasizes their importance encouraging drivers (in most cases parents) to always check if their children fastened up seat belts. Kids usually ignore their parents` advice finding it boring, so it should be parents` obligation to insist on buckling up before they start the car in order to increase their safety.
