A developer wants too use EL to invoke a function using S{my：bloof（“foof”）}. Which is always true？（）

• A、 The method invoked by this function must be statie.
• B、 The function class must implement the Function interface.
• C、 The expression is NOT a valid EL expression for invoking a function.
• D、 The function must be declared in a web.xml file using the  element.
• E、 The function class must have a method with the signature：Void bloof （java.lang.Strings）