Final answer:
"Tell me about your preferences and how you plan to use the TV." is the most effective open-ended question for identifying a customer's needs in purchasing a new television, as it encourages a detailed and personalized response.
Step-by-step explanation:
Out of the options provided, the best open-ended question to help a sales associate determine what kind of television is appropriate for a customer looking to purchase a new one is C - "Tell me about your preferences and how you plan to use the TV." This type of question allows the customer to share detailed information about their needs and preferences, such as where they will place the TV, what kind of content they like to watch, whether they are interested in smart TV features, or if they have any brand loyalty. These details will help the sales associate recommend a television that best fits the customer's lifestyle and usage plans.
Open-ended questions are incredibly valuable in retail sales as they give the customer space to express their desires in their own words, which is more likely to result in better customer satisfaction and potentially a better sales experience. They differ from yes/no questions or those with checkbox options, as they allow for more comprehensive and personalized responses.