The answer is "The employees can use sign language to communicate with Matt".
Explanation:
In this question, The personnel can interact with Matt via hand signals.Using the hand signals from the above alternatives, the interaction between the matt and other employees would be much more efficient.They could not only matt perform their work wisely with the hand signals, but it also allows him to feel integrated into the social group at the workplace.
i don't what you mean by, fragment-punctuated-correctly, but it is not "let's" because let's mean "let is" so that sentence would be punctuated incorrectly
