You forgot to add a story to the question... I would gladly help you tho ;)
"He exercised while I watch television." because the tenses of the verbs don't match--"exercised" is past tense and "watch" is present.
The answer would be B, it used personification to imply that running is exhilarating.
I phoned him because he was not home.
The second part of the sentence is now dependent on the first as it cannot stand alone as its own sentence.
