I would venture to guess that if 2a is empty, then 2b is checked.
Most likely you cashed out a whole life policy. There are several different types of whole life policies. One type that will generate a tax document of some type when cashed out, is one that earns interest or dividends. Most likely, that's the type you had. When you cash out the policy, the cash value paid out also includes the accumulated interest/dividends. That's why box 1 is most likely less than the amount of cash out value actually paid. So the amount in box 1 is taxable income to you in the tax year it was paid out.
