Imo. D
Premise: Parents of some of the children in a particular class have claimed that the teacher is not objective and favors his male students with higher grades.
Counter premise: But the record showed that 92% of the female students received a passing grade in this teacher's class.
Conclusion: This record demonstrates that the teacher has not discriminated against women when assigning grades.
There is a gap in the counter premise. What if the same test papers checked by another teacher and he gives more marks to the female students. So, the conclusion, that the teacher has not discriminated against women when assigning grades, is weakened.
The argument above is flawed in that it ignored the possibility that
A. a large number of the teacher's student were in his class the previous year. - Out of scope.
B. many teachers find it difficult to be objective when assigning grades to male and female students. - Out of scope.
C. the evidence shows that more than 92% of the female students should have received a passing grade. - Tempting, it says more female students must have received passing grade, but premise indicates that teacher assigns more grade to male students than female students. Hence, this option does not weakens the conclusion.
D. the majority of tests written by female students and that have been rechecked by another teacher were given a higher grade by the second teacher. - If this scenario happened, then conclusion is weakened as teacher has discriminated against women. So, this possibility is ignored in the argument.
E. the teacher is biased against female students in the case of only some of the subjects he teachers. - Irrelevant