Answer :
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.
Final answer:
The participle in the sentence is 'created,' which functions as an adjective describing who made the crossword puzzle.
Explanation:
Within the sentence provided, the word 'created' is the participle. A participle is a form of a verb that is used in a sentence to modify a noun or noun phrase and thus acts like an adjective. In this case, 'created' describes the crossword puzzle, indicating who made it. The word 'challenging' might seem like a participle, but it functions only as an adjective here, describing the crossword puzzle. Therefore, the correct answer is d. created.
