Answer:
it will prevent from rescuing them
Margot wanted to become a teacher
As a noun: He called security. <em></em>(<em>security is a noun</em>)
As an adjective: There are strict security measures (<em>describes what the measures are like</em>)
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.
I would say B, because fabric clarifies what yards is. Hopefully this helps and good luck!!!