Although its purpose is laudable, the exclusionary rule, which forbids a court to consider evidence seized in violation of the defendant’s constitutional rights, has unduly hampered law-enforcement efforts. Even when the rights violation was a minor or purely technical one, turning on a detail of procedure rather than on the abrogation of some fundamental liberty, and even when it has been clear that the police officers were acting in good faith, the evidence obtained has been considered tainted under this rule and may not even by introduced. In consequence, defendants who were undoubtedly guilty have been set free, perhaps to steal, rape, or murder again.

5. The author of the passage above assumes all of the following EXCEPT:

(A) The constitutional rights of criminal defendants should be protected.

(B) Most cases in which the exclusionary rule has been invoked have involved purely technical violations of constitutional principles.

(C) The number of cases whose outcome has been affected by the exclusionary rule is significant.

(D) Some of the defendants set free under the exclusionary rule have been guilty of serious criminal offenses.（B）

(E) Merely technical violations of the rules concerning evidence should be treated differently from deliberate assaults upon human rights

Chould someone tell me why the chioce is B? I am really confused by this one.

A is the basis of the exclusionary rule, has to be part of the assumption.
C is irrelavant, the number of affected cases has nothing to do with the effect of the exclusionary rule.
D is assumed because the statement "undoubtedly guilty."
E is assumed because of the statement "even when the rights violation was...a purely technical one."