Pledge refers to that in order to guarantee the performance of the creditor's right, the debtor or a third party transfers its movable property or rights to the creditor's possession. When the debtor fails to perform the debt, the creditor has the priority to be paid for the property in its possession.
According to the above definition, which of the following is a pledge?
Zhao borrowed 300,000 yuan from Liang, mortgaged his house to Liang at a price of 150,000, and registered the mortgage according to law