The correct answer is C: are. This question tests subject-verb agreement with collective nouns. A collective noun, such as "jury," can take either a singular or a plural verb depending on whether the group is acting as a single, unified entity or as individual members. When the members of the collective noun are acting separately or expressing differing opinions, as indicated by "divided in their opinions," the collective noun is treated as plural, and thus requires a plural verb.
In this sentence, the jury members are clearly not acting as one unit; instead, their opinions are split, highlighting the individual actions or thoughts of each member. Therefore, the verb must agree with the individual members, making "are" the appropriate choice. If the jury were acting as a single body, for example, "The jury has reached a verdict," then a singular verb would be correct. However, the phrase "divided in their opinions" explicitly signals individual actions, necessitating the plural verb "are."