________ that the trade between the two countries reached its highest point.

A．one doesn't need to take any medicine if he has a cold or the flu
B．aspirin should not be included in over-the-counter medicines for the flu
C．delayed treatment of the flu will harm the liver and central nervous system
D．over-the-counter drugs can be taken to ease the misery caused by a cold or the flu

A．are advised not to give them aspirin
B．should watch out for signs of Reye syndrome
C．are encouraged to take them to hospital for vaccination
D．should prevent them from mixing with people running a fever