A.I. Explanation:

Option 1: "In the back of the store."

Explanation: The text states that retailers commonly place their best-selling merchandise near the back of the store. This directly supports the answer, as it highlights the strategy used to influence customer purchasing behavior. The placement is a deliberate tactic to encourage customers to walk through the store, increasing the likelihood of additional purchases.

Option 2: "Near the front entrance."

Explanation: This option contradicts the information in the text, which clearly states that popular items are placed near the back of the store. Therefore, this option is incorrect as it misrepresents the location of popular merchandise.

Option 3: "Near worthless merchandise."

Explanation: This option is incorrect because the text does not mention anything about worthless merchandise. Instead, it emphasizes that popular items are strategically placed to attract customers, making this option irrelevant and misleading.

Option 4: "At cash counters."

Explanation: This option is incorrect as the text does not indicate that popular items are placed at cash counters. The focus is on the back of the store, making this option not only incorrect but also unrelated to the main idea presented in the text.