The correct option is A It harms the crops
The Great Leap Forward (1958) was a campaign undertaken by Mao, chairman of the People’s Republic of China to modernize China's economy. As a part of this campaign, hundreds of millions of sparrows were killed with the belief that they might eat the grain harvest. But the following year, 1959, it was noticed that insect infestation of crop fields had soared up and pests such as locusts lost their major predator, the sparrow. Thus the correct answer is option A.