OG详解-OG7 文法 Q13

Choice B is the best answer. The sentence contrasts the two songs, noting that “Poor Miner’s Farewell” is about coal miners in Kentucky, whereas “Bring Him Back Home” is about Nelson Mandela. 
Choice A is incorrect. The sentence emphasizes a similarity between “Poor Miner’s Farewell” and “Bring Him Back Home”; it doesn’t contrast the two songs. Choice C is incorrect. While the sentence provides a description of the song “Bring Him Back Home,” it doesn’t mention “Poor Miner’s Farewell” or contrast the two songs. Choice D is incorrect. While the sentence provides a description of the song “Poor Miner’s Farewell,” it doesn’t mention “Bring Him Back Home” or contrast the two songs.