The underlined pronoun <em>who </em>is used as a D) subject in this sentence. The subject is the doer of the action, the one who left mittens on the ground, in this case.
Answer:
Watching Tv may seem great but is it?
Well its a yes or no, Tv is good for a rainy day entertainment but its not something you should do every single day! Its not healthy! Playing outside used to be very popular before Tv's came around!
Explanation:
I just did a little bit to get you some ideas i will do more soon!
D because of its use of adjectives to describe nouns which paints an image that we can see in our mind.