Identify the best version of the sentences. The psychologist William James believed that facial expressions not only provide a visible sign of an emotion, actually contributing to the feeling itself.

Explanation: The original sentence uses the correlative conjunction 'not only... but also' implicitly and needs parallel structure. The phrase 'not only provide' requires 'but also' followed by a parallel verb form. 'Provide' is a simple verb form. Option 3: 'emotion **but also actually contribute** to the feeling itself' correctly pairs 'provide' (verb) with 'contribute' (verb) using 'but also'.