On Some Occasions, Attributing Students' Failures to Lack of Effort

On some occasions, attributing students' failures to lack of effort is quite appropriate. On other occasions, attributions to effort can backfire and be counterproductive. Which one of the following alternatives is the most accurate description of how attributions to effort can sometimes have adverse effects?

A) When students fail at a task they have tried very hard at and are then told that they didn't try hard enough, they may decide they simply don't have the ability to do the task and give up.
B) When students fail at a task at which they have not tried very hard to succeed and are then told that they didn't exert enough effort, they are likely to feel resentment toward their teacher.
C) When students are told that they didn't try hard enough at a task that they expended quite a bit of effort on, they will almost certainly attribute the failure to bad luck.
D) When students are told that they didn't exert enough effort and they really didn't try very hard, they are likely to attribute their failure to an external factor and not accept responsibility for it.