A: How long are you staying in London? B: I ..... in London for 2 months by the time I leave. Выберите один ответ will have been am going to

Ответ (EN):

1. I will have been in London for 2 months by the time I leave.

Перевод (RU):

1. Я пробуду в Лондоне 2 месяца к тому времени, как уеду.