一题英语阅读题，请给出答案和解释~！高分在线悬赏！满意追加！

这是我们英语期中考试裏的一题，刚开始老师的标答是A，结果后面好像在讨论改成C！而我选的是A！但这2分对我来说又至关重要！所以请各位高手回答到底选A选C！并给出解释！好让我信服或者有理由去和老师讨论答案！（我要的不仅仅是答案！主要是合理的解释！！！）

以下是原文及问题：

Mr. Evans works in Sydney. Last week he had a two-week holiday, but he didn’t know where to go. He said to his friend Robert, “I hate the hot weather here, but I can’t find a cool place in Australia. Where shall I take my holiday?”
‘That’s easy,’ said Robert, ‘You can go to Moscow. Snow and ice are covering the ground there now.’
Mr. Evans agreed with his friend. He bought a plane ticket and soon got to Moscow. He had a happy time there. But one day he got into trouble. After lunch he went to a park outside the city. He saw a dog following him while he was walking past a house. It was hungry and wished him to give it some food to eat, But he had no piece of bread or cake in his pockets. He tried to send it away, but it began to bark at him. Just at that moment, he saw a stone on the ground. He tried to pick it up but he couldn’t.
‘How strange these Russians are!’ Mr. Evans said to himself, ‘They do not tie their dogs, but firmly tie the stones!’
（ ） Mr. Evans couldn’t pick up the stone because ______.
A Russians tied the stone to the ground
B it was too heavy
C it was too cold

这题目出的很模糊~其实没有必要追究，不过如果非要一个结果的话，出题人的根据该是他朋友的话“Snow and ice are covering the ground there now”说明石头被冰结住无法捡起来

肯定是C，因为天气太冷，把石头和地冻结在一起，所以Mr. Evans 拿不起石头！！

我认为~A~不过我英语不是很好啦，才80多分，so，你~~~~~~ 首先，c的话，好像没什么关系啊，是因为Russians（俄罗斯人）把骨头系到地上了，所以Mr. Evans才拿不了骨头~~~~~~~~~~吧 【忽然认为ls的也很对~~~】

she is the “queen of detective novels” british writer agatha christie. agatha christie was born in devon county in 1890. when she was five she had already read a lot of books and tried to write novels. at the age of thirty, she had finished her first detective novel the mysterious affair at styles. in the novel, she molded a belgium detective hercule poirot. he is a little chap and has bending beard. he has many “gray brain cells” -reasoning factor, so he can always detection intelligently. he became the second famous detective after sherlock holmes. i esteem him very much. death on the nile is another famous book of agatha christie. and it had been film for a long time. many people like it very much. in agatha christie’s life, she had written over sixty detective novels and she deserves to be the “queen of detective novels”.