Final answer:
Under an exclusive listing agreement, an agent's most important action is marketing the property, focusing on advertising to potential buyers to ensure maximum exposure in the market.
Step-by-step explanation:
One of the most important actions an owner's agent is authorized to perform under an exclusive listing agreement is marketing the property. This entails using various strategies and platforms to advertise the property to potential buyers. An exclusive listing agreement usually gives the agent the right to be the only one to sell the property for a specified period, hence taking on the responsibility for ensuring maximum exposure of the property in the market. This does not typically include representing the buyer, as the agent's primary duty is to the seller. Moreover, the role of accepting rental applications falls outside the scope of selling the property and is generally not associated with an exclusive listing agreement for sales.