In the context of this essay, it would be "<span>4. Tan's mother does not speak standard English, but she is able to convey the ideas behind her words" that</span> best describes the meaning of this statement.
Her mom is okay with it, which surprises the girl.
the third one, if you add the comma without the when then you would have a comma splice (when you put a comma between 2 independent clauses without a conjunction) adding the when before Cynthia makes the first part a dependent variable and makes it okay to add the comma!
Hope this helps! :)
