Final answer:
The buyer's broker signs the Contract to Buy and Sell as a receipt for earnest money and to disclose their brokerage relationship, which are part of the procedural aspects in real estate transactions.
Step-by-step explanation:
The buyer's broker may sign the Contract to Buy and Sell for several reasons in the real estate transaction process. As a receipt for earnest money, the broker acknowledges the receipt of the earnest money that is part of the transaction, which in turn is held in escrow until the deal progresses. Furthermore, the broker's signature can serve as a formal documentation of their brokerage relationship with the client—a disclosure that's often required by law. However, ensuring the proper commission percentage is typically handled within the brokerage agreement and not within the Contract to Buy and Sell. Hence, the correct answers are that the buyer's broker signs the Contract to Buy and Sell as a receipt for earnest money and to disclose their brokerage relationship.