The figure below shows an HR diagram.What is the name for the feature marked "X"? 
Definitions:
Refrigerator
An appliance used for keeping food and drinks cold.
Deficiency
A lack or shortage of a necessary element or quality.
Chattel Mortgage
A loan arrangement in which an item of movable personal property acts as security for a loan, with the lender holding an interest in the property until the loan is repaid.
Bill Of Sale
A legal document that transfers ownership of personal property from the seller to the buyer.
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