Question 780849
Very theoretical question, certainly would not occur in practice.  
'
Think about what remains in the untraveled distance after each day's travel.  Always some distance remains between the man and his destination. Try to eliminate obvious wrong choices, and you have maybe a choice between "after long time" and "Never".  Any other choice obviously misses the "covers half the distance left" specification.  


Can find anything wrong with, "after a long time"?  That is NOT a number, and is unclear if it is a number.  


ANSWER:  D.  Never