A.I. Explanation:

Option 1: "car"

Explanation: The option 'car' does not fit the context of the sentence, which discusses central heating as a standard feature in living spaces. While cars are important, they are not directly related to the concept of standard amenities in homes.

Option 2: "office"

Explanation: The term 'office' is not appropriate here as the text focuses on central heating being a standard feature in residential settings, not workplaces. This option fails to align with the main idea of the text.

Option 3: "home"

Explanation: The word 'home' correctly completes the sentence, as it relates to the context of central heating being a standard feature in residential environments. The text emphasizes how central heating has transitioned from a luxury to a common necessity in homes.

Option 4: "park"

Explanation: The option 'park' is irrelevant in this context, as it does not relate to the discussion of central heating. Parks are outdoor spaces and do not typically involve amenities like central heating, which is specific to indoor living conditions.