In a psychological experiment conducted at Southbay University

Groups of men with various levels of education read stories in which people caused harm, some of them doing so intentionally, and some accidentally.
The less educated men, unlike the educated ones, assigned punishments that did not vary according to whether the harm was done intentionally or accidentally.

Conclusion: Uneducated men, then, do not regard people's intentions as relevant to penalization.

Since less educated men assigned punishments that did not vary according to whether harm was done intentionally or not, the conclusion says that uneducated men do not regard people's intentions as relevant to penalisation.

We need to weaken the conclusion above.

(A) In these stories, the severity of the harm produces was clearly stated.

Irrelevant. We need the relation between intention and penalisation.

(B) In interpreting these stories the listeners had to draw on a relatively feminine sense of human psychology in order to tell whether harm was produced intentionally or accidentally.

The participants had to read/listen to stories and interpret whether harm was produced intentionally or accidentally. So they were not given this information. They had to interpret it. Now, what if people with lower education found it hard to interpret whether harm was intentional or not? Then they would not base their penalisation on this factor. So this weakens our conclusion. It says that the observed result (less educated people ignored intentions) may not be because "uneducated men do not regard people's intentions as relevant to penalisation. " Instead, it may be because "uneducated men are unable to interpret whether harm was intentional or accidental".
This is correct.

(C) Relatively uneducated men are as likely to produce harm unintentionally as are more educated men.

Irrelevant. Level of education among perpetrators of the crime is not discussed.

(D) The more educated men assigned penalization in a way that closely resembled the way women had assign penalization in a similar experiment.

Irrelevant. No men vs women comparison.

(E) The less educated men assigned penalization that varied according to the severity of the harm done by the agents in the stories.

Irrelevant. It doesn't matter on what basis the less educated men assigned penalisation. Our conclusion is that they do not assign penalisation on the basis of intention. This option gives us one other factor on which they assign penalisation. So it doesn't weaken our conclusion. This option is nonconflicting with our conclusion.

Answer (B)