I HAVE NOT DECIDED THE DAY. I’LL GO TO LONDON ON THAT DAY. → A...

23. I have not decided the day. I’ll go to London on that day. → A. I have not decided the day that I’ll go to London. B. I have not decided the day when I’ll go to London. C. I have not decided the day where I’ll go to London. D. I have not decided the day which I’ll go to London.