Which two statements correctly differentiate functions and procedures?

Which two statements correctly differentiate functions and procedures? (Choose two.)

A.
A function can be called only as part of a SQL statement, whereas a procedure can be called only as a PL7SQL statement.

B.
A function must return a value to the calling environment, whereas a procedure can return zero or more values to its calling environment.

C.
A function can be called as part of a SQL statement or PL/SQL expression, whereas a procedure can be called only as a PL/SQL statement.

D.
A function may return one or more values to the calling environment, whereas a procedure must return a single value to its calling environment.