单选题 Young people's social environment has a ______ effect on their academic progress.
[A] gross [B] solid [C] profound [D] complete

【正确答案】 C

【答案解析】profound深刻的；gross全部的，总的；solid固体的；complete全部的。句意：年轻人的社会环境对他们的学业进步会有深刻的影响。