Final answer:
The mandatory aspects of training for Spartan boys included physical fitness and combat skills. Therefore, the correct option is D.
Step-by-step explanation:
The aspects of training that were mandatory for Spartan boys as part of their compulsory military service, starting at the age of seven, included both physical fitness (strength and endurance) and combat skills (hand-to-hand and weapons proficiency).
Boys were taken from their parents to live in barracks and were trained constantly in combat, maneuvering, and physical endurance. They underwent a severe regimen that included ritual beatings to make them physically strong and hardened warriors.
Therefore, the correct answer is D) Both physical fitness (strength and endurance) and combat skills (hand-to-hand and weapons proficiency).