Columnist: Donating items to charity may be a sign of generosity, but any generosity it may demonstrate is rarely a permanent virtue, since most donors make donations only intermittently. Which one of the following most accurately describes a flaw in the columnist's argument? ['The argument takes for granted that a character trait is present only when manifested.', 'The argument attacks the character of those whose values are different from those of the columnist.', 'The argument takes for granted that most people donate out of generosity.', 'The argument generalizes from too small a sample of cases.']