Yeesh!” Anastasia exclaimed. Finally giving her attention to the scene outside, she smiled. "Wow. It’s beautiful, isn’t it?” she said.

The author develops the character of Anastasia in this passage by using Anastasia’s dialogue

to clarify Keri’s dialogue.
to reinforce Keri’s dialogue.
as a contrast to Keri’s dialogue.
as an addendum to Keri’s dialogue.