Aubrey has been accepted into medical school, a most expensive undertaking. Aubrey has student loans and grants that pay part of the expense, but not all; she still needs $5,000. Aubrey asks her family friend, Clara, if Aubrey can borrow $5,000 and offers to pledge her mother's diamond necklace to ensure she repays the loan. Clara agrees and gives Aubrey $5,000. Aubrey insists that Clara take the diamond necklace and keep it until Aubrey repays all of the $5,000. To make sure that Clara's security interest is perfected, Clara needs to: file a written security agreement and financing statement, listing the necklace as collateral on both. do nothing, because she has possession of the necklace. file a written security agreement listing the necklace as collateral. file a written financing statement listing the necklace as collateral