I believe it should be the 3rd dot.
My friend, Alex, plays tennis.
My = possessive pronoun
friend = subject
Alex = an appositive (which is a noun that renames another noun right beside it) -- though not an adjective, it functions like one to explain which friend
plays = verb
tennis = direct object
hope this helps :)
Here the answer
Every sitcom episode has a main plot (story A), as well as one or two subplots (stories B and C).” There are three main acts, divided by two commercial breaks (in most American TV), with 3-5 scenes per act.