Choose the correct sentence: Выберите один ответ:
a. There was two bedrooms in my previous flat.
b. There were three rooms in my previous flat.
c. There is two bathrooms in my house.
d. There are a kitchen in my flat.

b. There were three rooms in my previous flat.

Объяснение:

b. There were three rooms in my previous flat.

Итак, смотрим.

Время (об этом нам подсказывает слово previous-предыдущий)-глагол в (were)...все верно

Подлежащее (rooms) во мн. чл.-конструкция тоже для мн.чл. (there were)