The correct answer is people and time . In insurance, mortality refers to the statistical measurement of death within a defined population. Insurers rely on mortality tables , which are developed using large pools of data that track the probability of death among groups of people over specific periods of time. These tables allow insurance companies to estimate the likelihood that individuals within certain age groups will die within a given year. The concept is based on the law of large numbers , meaning that when a very large group of people is observed over time, patterns of mortality become predictable and can be used to calculate insurance premiums.

Life insurance companies analyze mortality data across large populations and extended time periods to determine appropriate premium rates and to ensure that they maintain sufficient reserves to pay future claims. By spreading risk across many policyholders, insurers can accurately project expected losses and maintain financial stability.

The other options are incorrect because mortality statistics are not primarily based on income, geographic area alone, or personal characteristics such as hobbies or family history. The essential foundation of mortality calculations is large groups of people observed over time .