What three classes along with the Messaging.InboundEmailHandler are used to handle inbound
email messages in Salesforce? (No Answer)

A.
Apex code, Visualforce pages, and controllers
B.
Messaging.InboundEmail, Messaging.InboundEmailResult, Messaging.InboundEnvelope
C.
Messaging.InboundEmailHandler
D.
Make calls to methods using both valid and invalid inputs.