The correct answer is C)The pronoun “she” is used when describing the thoughts of Lizzie.
The line "Lizzie looked at him for a long time, tilting her head to one side as if trying to figure him out—which was what she was doing." is in third person point of view because no first person pronouns (I, me, my) are being used when describing Lizzie's thoughts. Second person pronouns (you, your, our) are neither being used when describing Lizzie's thoughts. This leaves third person point of view as the correct answer, since third person point of view involves the usage of pronouns such as "he", "she", "they" and "them".