Analysis of test questions: This question examines students' accurate understanding of the meaning of credit cards. In view of the information that it is difficult for people without stable income to apply for credit cards issued by banks, it can be seen that people without stable income have no guarantee for their credit status, so it can be judged that credit cards are a kind of credit certificates issued by commercial banks to customers with good credit status, and statement B is correct; A does not match the meaning of the question; The CD is wrong.