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.
Q: Question: When was the Society formed that contested the closing of the glen to the public? Passage:Glen Tilt (Scottish Gaelic: Gleann Teilt) is a glen in the extreme north of Perthshire, Scotland. Beginning at the confines of Aberdeenshire, it follows a South-westerly direction excepting for the last 4 miles, when it runs due south to Blair Atholl. It is watered throughout by the Tilt, which enters the Garry after a course of 14 miles, and receives on its right the Tarf, which forms some beautiful falls just above the confluence, and on the left the Fender, which has some fine falls also. The attempt of George Murray, 6th Duke of Atholl to close the glen to the public was successfully contested by the Scottish Rights of Way Society in 1847. The massive mountain of Beinn a' Ghlo and its three Munros Carn nan Gabhar (1129 m), Braigh Coire Chruinn-bhalgain (1070 m) and Carn Liath (975) dominate the glen's eastern lower half.
Links: a. Scottish Rights of Way and Access Society b. Beinn a' Ghlo c. Aberdeenshire d. Scotland
A:
a