The correct answer is B) The life expectancy is halved. The life expectancy of insulation materials is closely related to the operating temperature. As the temperature rises, the rate of thermal degradation and chemical reactions within the insulation increases, leading to a reduction in its lifespan. This relationship is often described by the rule of thumb known as the "10-degree rule" or the "Arrhenius equation," which states that for every 10°C increase in operating temperature, the life expectancy of the insulation is approximately halved. The other options are incorrect because: A) The life expectancy is not unaffected by temperature, as it is a well-established principle that higher temperatures reduce insulation lifespan. C) The life expectancy is not doubled, as it is halved for every 10°C increase. D) The life expectancy is not unpredictable, as the relationship between temperature and lifespan is well-understood and can be quantified.