Which of the following items may be placed in a broker's escrow account for use as an earnest money deposit?

An earnest money deposit is a demonstration of the buyer's commitment to purchasing a property, and typically, it consists of cash or check. This type of deposit is placed in a broker's escrow account to ensure that the funds are safely held until the transaction is finalized.

Using cash or checks as earnest money is standard practice in real estate transactions, as these forms are easily verifiable and can be processed smoothly through banking systems.

Other options, like a mortgage or deed of trust, are not typically used as earnest money because they represent a financing arrangement rather than an immediate monetary commitment. A promissory note signifies a promise to pay a certain amount at a later date, which also does not fulfill the immediate liquidity requirement for earnest money. Finally, stock certificates are not universally accepted as a form of earnest money deposit since they involve different regulations and may not be easily liquidated as cash when needed for a real estate transaction. Hence, cash or check are the most appropriate and commonly accepted means for earnest money deposits in a broker's escrow account.