"That's right." said the old man. "Ninety-nine years old, and I haven't an enemy in the world. They're all dead."
  "Well, sir." said the interviewer , "I hope very much to have the honour  of interviewing you on your hundredth birthday."
  The old man looked at the young man closely, and said, "I can't see why you shouldn't. you look fit and healthy to me!"
When the old man said, "I can't see why you shouldn't", what he meant was   _
"You must try to live another year to interview me again next year" "Of course you can see me again since you're so fit and healthy" "If I live to a hundred years, you should interview me again" "Unless you live another year, you wouldn't be able to interview me again"