A Jiangxi farmer, surnamed Zhu, has invented a machine that can remove kidney stones. His wife had her left kidney removed because of kidney failure, and stones were found in her right kidney later. However, surgery would be too dangerous for a woman with only one kidney. Zhu, 51, made a special bed which can vibrate with the power of the driving wheel of a tractor. Costing just 1,000 yuan, the bed successfully removed his wife's kidney stone. The invention was granted a national utility patent last year.

Why wouldn't the wife have surgery?

A. Because the family was poor

B. Because the wife was afraid of pain

C. Because it would be hazardous for her

（中國日報網英語點津 Helen 編輯）