Answer:
D. Ask listeners to change their personal values
Explanation:
Sorry if this is incorrect, but I believe it fits well with the conclusion.
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.
I think C is the correct answer, he is a 'skilled risk taker' most of the time. He was fooled only once, in that incident with the frog, but otherwise he always wins everything he competes in.
