A.I. Explanation:

Option 1: "Traditional heating systems"

Explanation: This option is incorrect because the text emphasizes the use of renewable energy sources and eco-friendly materials, not traditional heating systems. Traditional heating systems typically rely on fossil fuels, which contradicts the sustainable living theme presented in the text.

Option 2: "High-tech security systems"

Explanation: This option is incorrect as the text does not mention high-tech security systems as a feature of the houses. The focus is on sustainability and energy efficiency, making this option irrelevant to the question about reducing energy consumption.

Option 3: "Use of artificial lighting"

Explanation: This option is incorrect because the text states that the design of the houses maximizes natural light, which reduces the need for artificial lighting. Therefore, the use of artificial lighting does not contribute to reducing energy consumption.

Option 4: "Design that maximises natural light"

Explanation: This option is correct as the text explicitly states that each house is designed to maximize natural light, which directly contributes to reducing energy consumption by decreasing the reliance on artificial lighting. This aligns with the overall theme of sustainable living and energy efficiency presented in the text.