A、She wanted to decorate her home. B、She wanted to keep active. C、She wanted to improve her income. D、She wanted to get famous.

Grandma Moses is among the most celebrated 20th-century painters of the United States, yet she had barely started painting before she was in her late 70s. As she once said of herself: "[29]I would never sit back in a rocking chair, waiting for someone to help me." No one could have had a more productive old age.
    She was born Anna Mary Robertson on a farm in New York State, one of five boys and five girls. At 12, she left home and was in domestic service until at 27, she married Thomas Moses, the hired hand of one of her employers.[30]They farmed most of their lives, first in Virginia and then in New York state, at Eagle Bridge. She had 10 children, of whom 5 survived; her husband died in 1927.
    Grandma Moses painted a little as a child and made embroidery pictures as a hobby, but[31]only switched to oils in old age because her hands had become too stiff to sew and she wanted to keep busy and pass the time. Her pictures were first sold at the local drugstore and at a fair, and were soon spotted by a dealer who bought everything she painted. Three of the pictures were exhibited in the Museum of Modern Art, and in 1940 she had her first exhibition in New York. Between the 1930’s and her death she produced some 2,000 pictures: detailed and lively portrayals of the rural life she had known for so long with a marvelous sense of color and form. "I think real hard till I think of something real pretty, and then I paint it. " she said.
29. What can we learn about Grandma Moses?
30. What did Grandma Moses do in most of her life?
31. Why did Grandma Moses begin to paint according to the passage?