Choice "A" is correct. Perfection by taking possession requires the secured party to take possession of the collateral, and that is what happens when a pawnbroker lends money − the pawnbroker gives a person money in exchange for an item of personal property, which the person may redeem by paying back the pawnbroker.
Choice "d" is incorrect. Mortgages on real estate are not even within Article 9, but in any case, a mortgagee (the lender) does not usually take possession of the mortgaged premises; rather the mortgagor (usually the borrower) usually retains possession.
Choice "b" is incorrect. A wholesaler usually keeps possession of the inventory collateral, since it is difficult to sell if the secured party has possession.
Choice "c" is incorrect. Usually when a consumer buys a car, the secured party does not maintain possession of the collateral.