Final answer:
Option (a), In the book 'Resistance,' Chaya's grandmother spoke Yiddish, which is indicative of the Jewish heritage and cultural background during World War II.
Step-by-step explanation:
In the book Resistance, Chaya's grandmother spoke Yiddish. This detail is significant as it highlights the cultural background of the characters within the historical context of World War II. Chaya's Jewish heritage is a central aspect of the story, which is set during a time when many European Jews, especially those in regions like Warsaw, spoke Yiddish in their daily lives.
It's important to understand that knowledge of languages spoken by different communities can offer insight into their experiences and histories, such as the courageous counterattack by Polish Jews in the Warsaw ghetto during the Holocaust.