If Jan, a single mother, dies at age 40, what would her only son receive as a one-time lump-sum benefit?

The correct amount for a one-time lump-sum death benefit under Social Security is $255. This benefit is intended to assist the family with funeral and other immediate expenses incurred due to the loss of a wage earner or insured individual. It is a standard amount established by Social Security and does not vary based on the income or work history of the deceased.

Other amounts listed in the options exceed the standard lump-sum benefit and are not applicable in the context of Social Security's regulations regarding death benefits. Therefore, only the amount of $255 aligns with the established policy for a one-time death benefit provided to the eligible survivor, which in this case would be Jan's son.