Mary is a high$-$net$-$worth individual who is $66$ years old. She was surprised to find out she was eligible for Social Security retirement benefits, since she has substantial retirement income. She is overlooking which characteristic of Social Security?

Social Security benefits are not related to earnings during working years

Social Security retirement benefits are not means tested

the Social Security retirement program is well funded and can afford to provide benefits to high$-$net$-$worth individuals

adequate funding of Social Security is not necessary