Final answer:
True, Agamemnon and Menelaus are brothers, with Agamemnon being the king of Mycenae and Menelaus the king of Sparta, their relationship being part of the narratives surrounding the Trojan War.
Step-by-step explanation:
Agamemnon and Menelaus are indeed brothers, which makes the correct answer to your question a. True. They are significant figures in Greek mythology, notably in the tales of the Trojan War. Agamemnon was the king of Mycenae and the commander of the Greek forces, while Menelaus was the king of Sparta, and his wife, Helen's, abduction by Paris of Troy was the catalyst for the Trojan War.