The principle of seesaw reciprocity refers to the interaction between people. Just like sitting on a seesaw, one end cannot be fixed at one end and the other end is low, but must be alternated. Therefore, people usually reward others for what they have done in an appropriate way. Everything, because acceptance is often tied closely to the obligation to repay. Based on the above definitions, which of the following is the following that reflects the principle of reciprocity of the seesaw? ['Donating a rose gives you a fragrance. You do n’t ask for rewards for good deeds.', 'In order to reduce the default rate of customer orders, the salesperson usually asks whether the customer will fulfill the promise as promised before the end of the contract.', 'We like people who are similar to us, regardless of whether the similarities are in perspective, personality, background or lifestyle.', 'After a stationery store launched the service of water delivery when entering the store, the sales of stationery increased significantly.']