Which of these statements is true about grandparents in the U.S.?

Which of these statements is true about grandparents in the U.S.?
 
  a. The number of grandparents raising grandchildren increased in recent years.
 b. Multigenerational families usually form because the grandparents need assistance.
 c. Multigenerational households were much more common in the past.
 d. Most multigenerational families are formed because a mother does not want to give up her adult children.

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The authors of the text argue that
 
  a. divorce may be seen as believing marriage is very important.
 b. the high rate of out-of-wedlock birth is a clear indicator of a decline in the value of marriage.
 c. the divorce rate is rising because Americans are getting married at increasingly younger ages.
 d. all unwed mothers must be considered single parents.