Question worth 45 points! Please help asap!! Which line from “Babysitting” reflects the climax of the plot and supports an important theme?

from Babysitting
10 "I'll leave you to your babysitting." She said that last word with a laugh as she quickly typed on the tiny keyboard in her hands. "Sorry that's how you have to spend your afternoon."
Sam got an idea. He knew if he just used the right approach, he could get Tanya's interest.
"Actually, I have to go, too."
Tanya looked up from her smart phone. "Why?"
11 "Well, she's going to be walking soon, and my parents and I have been trying to predict who's going to get her to do it. I have a feeling that today is the day."
"Ah hah!" Tanya was wiggling her fingers at Kristi who was laughing in response.
"Yeah, it's really cool to watch her. She crawls around and she's almost ready to stand on her own. I'm sorry that you can't join me."
Tanya wiggled the fingers on both hands.
12 "Where does she like to be?"
"The playroom," Sam said and handed his wriggling sister into Tanya's open arms.
Tanya rubbed her nose against Kristi's. "I just bet cousin Tanya can get you walking! Come on, sweetie!"
Tanya took Kristi into the playroom.
13 "What about your movie?" Sam asked, fingers crossed, hoping Tanya did not pick up on his duplicity.
"It will be playing for months," Tanya called. "Kristi's first steps are a once-in-a-lifetime moment!"
Sam smirked, flopped down on the couch, and turned up the basketball game.

Answers to chose from
(Sam got an idea. He knew if he just used the right approach, he could get Tanya's interest.)
("Well, she's going to be walking soon, and my parents and I have been trying to predict who's going to get her to do it)
(Tanya rubbed her nose against Kristi's. "I just bet cousin Tanya can get you walking! Come on, sweetie!")
(Tanya rubbed her nose against Kristi's. "I just bet cousin Tanya can get you walking! Come on, sweetie!")