单选题 You could refuse to ______ your Social Security number except for Social Security purposes, which is all that the law requires.
A. expound B. divulge C. apprehend D. unriddle

【正确答案】 B
【答案解析】[解析] expound“详细说明，解释”；divulge“泄露，暴露”；apprehend“领会，理解”； unriddle“阐明”。