Final answer:
User accounts can be altered and dropped using the Structured Query Language (SQL), which is the correct answer to the question and a common language for managing relational databases.
Step-by-step explanation:
User accounts may be altered and dropped using the Structured Query Language (SQL). The correct answer to this question is a) SQL. SQL is a standardized programming language used for managing and manipulating relational databases. It provides commands to perform tasks such as creating, altering, and deleting database objects, including user accounts. While NoSQL is a class of database management systems that do not use SQL, and CassandraQL and CQL are query languages associated with specific NoSQL databases (Apache Cassandra), they are not the standard languages used for common databases operations, especially altering and dropping user accounts, which are typically managed within SQL databases.