Which of the following is accurate regarding income statistics?

a. Current annual income is also an accurate indicator of relative economic status for the same individual over a longer period such as a decade or lifetime.

b. When there is substantial income mobility, one's current position in the income distribution will not be a very good indicator as to what one's position will be a few years in the future.

c. Recent studies indicate that there is a strong positive relationship between the relative income position of a family and the relative income position of their children and grandchildren.

d. Even though annual income data camouflage the fact, high-income earners generally maintain their status year after year, while those with low current incomes tend to stay poor year after year