2. A is B was C were D has been

Решение:

Предложение "when she was just 18 years old. She began the story when she 2 ______ living with her future husband..." описывает состояние персонажа в прошлом. Глагол "was" (была) в прошедшем времени идеально подходит для описания возраста и состояния героини.

Ответ: B was