进行绿叶中色素的提取和分离实验时，用于防止色素被破坏的试剂是

根据短文理解，从给出的A、B、C三个选项中选择最佳答案填空。

    My feeling about science have really changed. I never used to 1 science, but last year, I changed schools, and the science 2 at my new school were excellent. The science facilities are very 3, with laboratories that have all the latest equipment. Our chemistry teacher, Mr. Longford, take us to public science lecture (讲座) about for times a term, and these are 4 very interesting, as the lectures are people who have made real discoveries in 5 area of science. The fact is, Canada has 6 first-class scientists. In the last twenty years, seven Canadian scientists have won the Nobel Prize! The Nobel Prize is the highest scientific Prize, so we should be very  7 of that.

    I'm becoming more and more interested in physics, and have decided that I want to 8 it at university. I'm going to try to go to  9 Montreal or Ottawa University, as both are supposed to have good Physics Departments. My parents are quite 10. They always thought I would become an English teacher.