I can’t remember when I last saw him, but it’s certainly a long time ago.

A.  I’d like to forget how many years have passed since I last saw him.

B.  I shall never forget meeting him even though it’s a long time ago.

C.  I only know it is ages since I saw him and I can’t remember when that was.

D.  We’ve only met once and that was too long ago for me to remember him.