You forgot to mention that this question is about "Anne Frank's diary".
As you already know, Anne Frank and her family along with other Jews, was hidden in a room above the office of her father's company, while they waited for the war to end and the Jews to live freely.
They had help from office workers who protected them and provided all the resources they needed, these workers were called: Victor Kugler, Johannes Kleiman, Miep Gies and Bep Voskuijl
Anne Frank's older sister had a personality very different from hers, was more restrained and introspective, becoming less exuberant than Anne, her name was Margot.
c because it gives a negative reason to why they should think twice