Задайте вопросы к предложению :
She has been flying over the ocean for 3 hours.
a) yes/no;                 b) where (how long);                c) who

a). Has she been flying over the ocean for 3 hours?
b) How long has she been flying over the ocean?
Where has she been flying for 3 hours?
с) Who has been flying over the ocean for 3 hours?