Answer:
The correct answer is, Low income.
Explanation:
The crucial stratification variable in the well being of the elderly is Low income, which causes a lifetime of stresses including less education, less health care, and accumulating disadvantages of many kinds.
Low income is the main stratification variable which is the base of all stresses and problems. When a person's income is low, he would not be able to keep his living standards during after the retirement, which means he would encounter stresses in elderly or old age. Low income would cause stresses like less education, less health care, less living standards, etc.