单选题 The passage suggests that the amount of time it takes to observe a gamma burst from a fireball would be increased if

(A) the fireball in question expanded at a greater rate than normal
(B) the fireball in question expanded at a slower rate than normal
(C) the fireball in question occupied less space than normal
(D) the fireball in question occupied more space than normal
(E) the fireball in question failed to sweep up surrounding gas clouds

A
B
C
D
E

【正确答案】 B

【答案解析】