Answer: The prepositional phrase that can be added to the sentence provided is "with his friends".
Explanation:<u> A prepositional phrase is a phrase that includes a preposition, its object and, in some cases, words that modify that object.</u> Moreover, a prepositional phrases usually modifies a verb or a noun. <u>"With his friends" is the only prepositional phrase among the options</u>; therefore, it is also the only one that can be added to the sentence "Kenny played video games".<u> "With his friends" has been introduced by the preposition "with"</u>. In contrast, neither of the other phrases has been introduced by a preposition.