A.I. Explanation:

Option 1: "When you really smile, the muscles around your eyes move 10 percent more than a fake one."

Explanation: The text states that 'the muscles around the eyes shift 10 percent more for a real smile than they do for a fake one.' This directly supports the claim made in this option, confirming that the movement of the eye muscles is indeed greater during a genuine smile compared to a fake one.

Option 2: "Software can recognize people's facial expressions to determine whether people pretend to smile."

Explanation: The passage explains that researchers trained a program to detect genuine smiles by analyzing facial expressions. This aligns with the statement that software can recognize facial expressions to differentiate between real and pretended smiles, as the program evaluates the differences in muscle movements.

Option 3: "The program can track and identify specific details around the eyes, cheeks and mouth."

Explanation: The text mentions that the program can 'examine a video clip of a human head and identify specific details around the eyes, cheeks and mouth.' This confirms that the program is capable of tracking and identifying these specific facial features, making this statement accurate.

Option 4: "It's hard for the naked eye to tell whether people really laugh or pretend to laugh."

Explanation: The passage does not provide any information regarding the difficulty of distinguishing between real and fake laughter with the naked eye. Instead, it focuses on the program's ability to detect these differences, suggesting that there is a method to discern genuine emotions, which contradicts the implication of this option.

Option 5: "Sometimes people smile because they are polite rather than happy."

Explanation: While this statement may be true in a general context, the passage does not mention anything about politeness or the reasons behind smiling. Therefore, it is not supported by the text and is considered irrelevant to the main idea presented.