A. Use an @id property that constructs a private field as a concatenation of two columns.

B. Use a separate class to map those two columns and use an @idclass annotation to denote I primary key field or property in the entity.

C. Use a separate @Embeddable class to map those two columns and use an @EmbeddedId annotation to denote a single primary key field or property in the entity.

D. Use a separate @Embeddable class to map those two column and add two fields or properties the entity, each marked as @id, that correspond to the fields or properties in the embeddable class.

E. Use a separate class to map those two columns. Specify that class using @Idclass annotation on the entity class. Add two fields or properties to the entity, each marked as @Id, that correspond to the fields or properties in that separate class.