Final answer:
In the book 'Resistance,' Jews were mandated to wear a yellow Star of David on their arm, used to identify and segregate them during the Nazi occupation.
Step-by-step explanation:
In the book Resistance, Jews were required to wear a yellow Star of David on their arms. This star was used during the Nazi occupation to identify and segregate Jewish people from the rest of the population, and the requirement to wear it was a form of persecution. The correct answer to which symbol Jews were required to wear on their arm during this time is (a) A yellow Star of David.