B. them. That is the unacceptable word in the sentence.
No, this is not a run-on sentence
Show me more info....on Mr Lacey and his trip at the pound where he saw dogs I presume
I would say that the parallel list here is C) a lost puppy, a colored poster, and a happy boy.
This is because all words have an article <em>a, </em>and an adjective in front of them, so they are parallel.
