Answer:
She feels that she should have written more about the boys she knew.
Step-by-step explanation:
'The Diary of a Young Girl' is a memoir written by Anne Frank while living in hiding at 'annex.'
In her diary entry dated June 15, 1942, she added a comment while she was reviewing her diary after a year and a half. In her added comment she feels that she should have written more about the boys she knew from her class.
And in her added comment, then, she goes on writing about the boys she knew from her class describing each of them.
Therefore, the correct answer is option C.