Final answer:
The word 'vitality' most closely matches the word 'energy' because it refers to being strong, energetic, and full of life, which is an essential component of one's overall well-being.
Step-by-step explanation:
Of the options given, energy matches the word "vitality" most closely. Vitality refers to the state of being strong, energetic, and full of life. When we talk about vitality in a health context, we often refer to energy as an essential component of one's overall well-being and ability to perform daily activities. Stamina, hardiness, and endurance are somewhat related concepts, but they specifically denote the ability to sustain prolonged physical or mental effort, the ability to withstand tough conditions or stress, and the capacity to endure an unpleasant or difficult process or situation without giving way, respectively.
Therefore, the correct option is d) energy.