resolve the paradox

[paes]

Parents often criticize schools for not doing their job. Many blame schools for low student achievement scores. Surprisingly, the most frequent and vociferous complaints come from those who live in districts where the achievement scores are high.

All of the following, considered individually, help to explain the apparent paradox EXCEPT:
A. Parents from districts of high achievers are very involved with the schools and are, therefore, more likely to make critical comments.
B. Parents have no knowledge of their district's own scores.
C. High scores cause parents' expectations to rise leading parents to demand that students achieve even more.
D. High-scoring districts contain low-achieving students whose parents are likely to complain when their children score below the local average.
E. Most complaints about schools come from political activists, most of whom live in high-achieving districts.

I am stuck between B and E.

[akhpad]

B. Parents have no knowledge of their district's own scores.
=> might be high score and Complain
=> might be low score and Complain

E. Most complaints about schools come from political activists, most of whom live in high-achieving districts.
=> political activists do not relate with student activities.

I believe that B is more vague. Hence, I can be B.

[tnaim]

IMO D. what's the source of the question and official answer?

[paes]

OA B
source : 800scores

I selected E, could not find any valid explanation to eliminate E.