Instructions: In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.
Input: Question: Was Thrace the capital of a nation? Passage:Bulgaria was focused on actions in Thrace and Macedonia. It deployed its main force in Thrace, forming three armies. The First Army (79,370 men), under general Vasil Kutinchev with three infantry divisions, was deployed to the south of Yambol, with direction of operations along the Tundzha river. The Second Army (122,748 men), under general Nikola Ivanov, with two infantry divisions and one infantry brigade, was deployed west of the First and was assigned to capture the strong fortress of Adrianople (Edirne). According to the plans, the Third Army (94,884 men), under general Radko Dimitriev, was deployed east of and behind the First, and was covered by the cavalry division hiding it from Turkish view. The Third Army had three infantry divisions and was assigned to cross the Stranja mountain and to take the fortress of Kirk Kilisse (Krklareli). The 2nd (49,180) and 7th (48,523 men) divisions were assigned independent roles, operating in Western Thrace and Eastern Macedonia respectively.
Links: a. Tundzha b. Vasil Kutinchev c. Thrace d. Edirne
Output:
c