Deposit: The parties agreed in writing that one party should pay to the other party as a certain amount of currency secured by the creditor's rights. If the party paying the deposit fails to perform the agreement, it is not entitled to request the other party to return the deposit; if the party receiving the deposit fails to perform the agreement, it must double the amount to the other party Refund the deposit. which of the following are deposits? ["A urgently needs cash and wants to sell his real estate. When A's friend B learns, he first lends 10,000 yuan to A for emergency. A writes down a document and promises to sell the house to B at a price lower than the market price.", "B intends to purchase A's set of real estate, A receives 20,000 yuan from B, and guarantees in writing that if the transaction cannot be completed because of A.20,000 yuan will be returned to B, and B will be compensated for 20,000 yuan; if the transaction is not completed because of B, Then A does not refund the 20,000 yuan.", "According to the intermediary introduction, A has a purchase intention for B's set of real estate, but it still needs to be considered. The intermediary charges A a 10,000 yuan sincerity money, and states that if A eventually gives up the purchase, the 10,000 yuan can be returned.", 'A real estate company collects 20,000 yuan each from customers who intend to purchase the property before its official sale, and promises that when these customers purchase the real estate, they will get a discount of 40,000 yuan than the original price.']