Definition: 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: Which of the armies involved in the Action of 22 Augst 1917 had more men? Passage:The Action of 22 August 1917, took place in the First World War, in the Ypres Salient on the Western Front during the Third Battle of Ypres. The engagement was fought by the Fifth Army of the British Expeditionary Force and the German 4th Army. During the Battle of Langemarck (1618 August), the British had advanced north of the village but had been defeated further south and failed to capture the , the third German defensive position. At a conference with the Fifth Army corps commanders on 17 August, Gough arranged for local attacks to gain jumping-off positions for another general attack on 25 August. At the Action of the Cockcroft on 19 August, XVIII Corps and the 1st Tank Brigade had captured five fortified farms and strongpoints for a fraction of the casualties of a conventional attack.
Links: a. Fifth Army (United Kingdom) b. 4th Army (German Empire) c. Battle of Langemarck (1917) d. British Expeditionary Force (World War I)
Output:
a