Which lease agreement can potentially provide income growth tied to the economy?

The index lease is the correct answer as it is specifically designed to adjust rental rates based on a specific economic index, such as the Consumer Price Index (CPI) or another relevant economic indicator. This means that as the cost of living or other economic variables increase, so too can the rent. This type of lease allows landlords to benefit from potential income growth as it ties rent increases directly to economic conditions, providing a safeguard against inflation and ensuring that rental income keeps pace with market trends.

In contrast, a net lease typically requires the tenant to pay a portion of the property expenses in addition to the rent, but it does not inherently include provisions for adjusting rent based on economic conditions. A graduated lease has predetermined increases in rent at specified intervals but does not link those increases to measurable economic indicators, which means it lacks the responsiveness of an index lease. Lastly, a reappraisal lease involves rent adjustments based on a formal reappraisal of the property value and may not directly correlate to broader economic conditions in the same way an index lease does. Therefore, the index lease stands out as the option that most clearly ties rental income to the economy and economic growth.