You are creating a custom content type named CT1.

You need to use a Feature to add an existing site column named SiteCol1 to CT1.

Which code segment should you include in the Feature?

A.
<Field ID=”SiteCol1″/>

B.
<Field ID=”{XXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXX}” Name=”SiteCol1″/>

C.
<FieldRef ID=”SiteCol1″ Name=”{XXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXX}”/>

D.
<FieldRef ID=”{XXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXX}” Name=”SiteCol1″/>

Explanation:
MNEMONIC RULE: “existing Field needs to be Referenced”

FieldRef Element (ContentType)
http://msdn.microsoft.com/en-us/library/aa543225.aspx