A. - It's not exactly necessary to tell her friends..
B. - It's best off to point out what's wrong with her grammar rather than making Tammy lost or confused of what was wrong..
C. - This is mostly the correct answer due to her telling Tammy it is correct and pointing where it's out and then tells/explains how to improve it..
D. - I don't know if this counts as plagiarizing in some way but if Tammy's paper is unimproved in it's own way then Jenna would also have a badly written essay and a terrible grade to say at the very least.
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- Akamatsu