Answer: We know for sure that there is an established relationship between Casey and Mabel.
Explanation: "She has met Mabel, a kind elderly blind lady who has asked Casey to spend an hour each day helping her around the house".
D. parallel structure just means that all of your verbs in the comma series line up in regards to tenses, here. in choice D, it's "BE friendly," "INTRODUCE yourself," and "SMILE." these are all present tense verbs.
the rest of the choices don't match--"exercise" and "stretching" are two different verb forms in choice A, "to go to the library" is the odd one out in choice B, ane "to build" doesn't match with the "-ing" verbs in choice C.
<span>C. An argument uses facts, emotions, and credibility to persuade an audience to believe something.</span>
