Here the story isNila, a young girl of 14 is a student of class 9 of Noapara Girls High School, Noapara. She was a poor girl but had an aspiration to help her family for a better life. On her way to school, a boy named Alam used to tease her very often. But she didn't frustrate rather

Nila, a young girl of 14 is a student of class 9 of Noapara High school, Noapara. She was a poor girl but had an aspiration to help her family for a better life. On her way to school, a boy named Alam used to tease her very often. But she didn't get frustrated.

rather

She used to tell the boy not to disturb her. But the boy was very naughty. he did not pay heed to her speech. He started to disturb her again and again. Then, Nila thought a little bit what to do. She made a plan to change the boy's characters. Nila offered they boy. If you're able to change your life, I'm ready to marry you. By listening her proposal, the boy agreed to study well and completed his graduation. Fortunately he got a government job. At last, they got married and became happy. By this way, they helped both of their family.

the answer to "what does the narrator realize by the end of the story" is b.