A section of a Visualforce page that allows users to enter input and then submit it with an
<apex:commandButton> or <apex:commandLink>. The body of the form determines the data that
is displayed and the way it is processed. It’s a best practice to verify that pages and custom
components use at most one <apex:form> tag.
As of API version 18.0, this tag can’t be a child component of <apex:repeat>.
A.
apex:form
B.
apex:chart
C.
apex:actionRegion
D.
apex:insert