And the Winner Is

Even though it was her first experience as a babysitter, Nina felt she had been staring intently at the same checkerboard for a bewildering amount of time. She had spied the move that could easily win her the game several turns ago, but she knew it would crush Lynn's heart if she made it. Nina had just taught her cousin how to play checkers while their parents were out, and she was even enjoying her first time as a "responsible" babysitter. She didn't think she should do anything to rock the boat and make Lynn upset. She also wanted Lynn to feel encouraged that she was learning to play a new game—especially a game like checkers that relies on strategy to win.
"I don't know where to move next," whined Lynn, breaking into Nina's thoughts. "Can you help me?"
This was an opportunity to "do the right thing," as Nina's mother had always told her. She thought that she should forget about winning and help her cousin learn checkers.
"You don't know what to do?" joked Nina. "Then it looks like I might win!"
"Stop, Nina," said Lynn. "You have to help me. You're my babysitter! And you're my older cousin and my checkers teacher, too!"
Nina laughed. "You're right," she admitted. "I can't make you win, but I can certainly show you how to block my move." She reached toward the black and red game pieces to help explain the next move.
"Thanks," smiled Lynn.
Based on the evidence in the passage, Nina can be described as
A. competitive.
B. meek.
C. observant.
D. naive.