A、His advanced age. B、His children’s efforts. C、His improved financial condition. D、His second wife’s positive influence. D文中说话人

"Loving a child is a circular business. The more you give, the more you get, the more you want to give," Penelope Leach once said. What she said proves to be true of my blended family. I was born in 1931. As the youngest of six children, I learned to share my parents’ love.[19]Raising six children during the difficult times of the Great Depression took its toll on my parents’ relationship and resulted in their divorce when I was 18 years old. Daddy never had very close relationships with his children and drifted even farther away from us after the divorce.
    Several years later a wonderful woman came into his life, and they were married. She had two sons, one of them still at home. Under her influence, we became a "blended family" and a good relationship developed between the two families. She always treated us as if we were her own children.[20]It was because of our other mother—Daddy’s second wife—that he became closer to his own children. They shared over twenty-five years together before our father passed away. At the time of his death, the question came up of my mother—Daddy’s first wife—attending his funeral. I will never forget the unconditional love shown by my stepmother when I asked her if she would object to Mother attending Daddy’s funeral. Without giving it a second thought, she immediately replied, "Of course not, honey—she’s the mother of my children."
19. According to the speaker, what contributed to her parents’ divorce?
20. What brought the father closer to his own children?
21. What message does the speaker want to convey in this talk?