A
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?
A: The argument takes for granted that a character trait is present only when manifested.
B: The argument attacks the character of those whose values are different from those of the columnist.
C: The argument takes for granted that most people donate out of generosity.
D: The argument generalizes from too small a sample of cases.