Answer:
i'm so sorry for your loss, i know how hard it is
Explanation:
<3
If the underlined phrase is <em>having been warned by her mother, </em>then this is a nonessential perfect participial phrase.
Nonessential phrases are separated from the rest of the sentence by commas, and since this is a perfect participle, this is the only correct option.
C is grammatically correct
to study it and understand its emtions