I ate the soup. After that I remember that I had forgotten to give my little sister some of it.

Translation: I eat soup. Then I remembered that I forgot to give my sister some

A. It wasn’t until I ate the soup that I remembered that I forgot to give my sister some. ⇒ Do not choose A due to the structure: It was not until… that…: until…

B. As soon as I remembered that I forgot to give my sister some, I ate it.

C. Only after eating the soup did I remember that I forgot to give my sister some.

D. As soon as I forgot to give my sister some soup, I ate it.