求助普样语法

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普-4
5. In an area first explored by Samuel de Champlain, ______ .
(A) establishment of the city of Halifax in 1749
(B) in 1749 the city of Halifax established
(C) in 1749, establishing the city of Halifax
(D) the city of Halifax was established in 1749
答案给的c,我觉得选d
34. Xanthines have both (good and bad) effects on the body, and these effects are (generally) (determined) on the size and (regularity) of dosage.
选c