问题

The bikes produced in that factory are of highquality So they ______ well both at home and abroad
A:enough tired to go to bed
B:too tired to go to bed
C:so tired that he went to bed
D:very tired, he went to bed
B:too tired to go to bed
C:so tired that he went to bed
D:very tired, he went to bed
正确答案是: