Questions 24 to 26 are based on the following news, At the end of the news item, you will be given 15 seconds to answer the questions. Now listen to the news. According to the Vance-Owen plan, Sarajevo would be controlled by ______.

A．Farmers should use less insecticides.
B．Farmers should use a combination of two or three insecticides at once.
C．At certain times of the year, farmers should actually try to attract new insects onto the crops they are trying to protect.
D．Farmers should regularly spray crops as a precaution against problems that are caused by large numbers of pests.

A．on
B．at
C．in
D．under