1.Is ( )you told me really true?A that Bwhich C it Dwhat

1.Is ( )you told me really true?A that Bwhich C it Dwhat
2.No one knows exactly( ) this important discovery was made.
A that Bthat how and when Chow or why D how or when
3.( )came to see me?
A Who you think B Do you think who CWho do you think D Whom do you think