Verified answer

"Have you been to the Tower of London?" Mary asked me. Mary asked me ..... to the Tower of London.

a) had i been b)whether i was

c) if i have been d) if i had been

Verified answer

"Have you been to the Tower of London?" Mary asked me. - "Вы когда-нибудь были в лондонском Тауэре?" - спросила меня Мария.

Mary asked me if I had been to the Tower of London. - Мария спросила меня,  была ли я  в лондонском Тауэре.