A.You have the correct e-mail address.

B.HTML does not work in sandbox, make sure your e-mail has no HTML.

C.Look at the system audit trail.

D.Check the deliverability settings.

A.Post

B.Poll

C.Email

D.File

E.Create

A.Master-Detail relationships cannot be converted to a look-up relationship.

B.Standard objects can be on the detail side of a custom object in a Master-Detail relationship.

C.Master-Detail relationships can convert to a lookup relationship if no roll-up summary fields exist on the master object.

D.A Master-Detail relationship cannot be created if the custom object on the detail side already contains data.

E.Deleting a master record in a Master-Detail relationship deletes all related detail records.

A.Check the required field box for the field on the record type.

B.Creating a validation rule for the field.

C.Check the required field box on the page layout.

D.Create a Workflow Rule.

E.Check the required field box on the field definition.

A.Person accounts do not have a "Parent Account" field.

B.Person Accounts can be enabled in setup.

C.Person accounts do not have the Account Hierarchy feature.

D.Leads cannot be converted to Person Accounts.

E.Person accounts can have contacts.