Question: What is the function of the `@Transactional` annotation at the class level?

1. It's a transaction attribute configured by `spring.security.transactions.xml` config file that uses Spring's transaction implementation and validation code.
2. It's a transaction that must actively validate by the bytecode of a transaction using Spring's `TransactionBytecodeValidator` class. Default Transaction behavior rolls back on validation exception but commits on proper validation
3. It creates a proxy that implements the same interface(s) as the annotated class, allowing Spring to inject behaviors before, after, or around method calls into the object being proxied.
4. It's a transaction that must be actively validated by Spring's `TransactionValidator` class using Spring's transaction validation code. Default Transaction behavior rolls back on validation exception.

Answer: The correct answer of the above question is Option C:It creates a proxy that implements the same interface(s) as the annotated class, allowing Spring to inject behaviors before, after, or around method calls into the object being proxied.