The way to improve education is to divide schools by gender, so that males and females are taught separately.

which sentence provides the best supporting evidence for the claim?

if students spend even 10% of their time being distracted by the opposite gender, then that is just silly.
my dad has been a teacher since 1993, and i think he does fine teaching in a school that has only male students.
at least 50% of my class is the opposite gender, and the amount of time they are distracted by the opposite sex is minimal.
a 1993 study showed that teachers tend to favor males over females, thereby creating an inequality in mixed-gender schools.

The correct answer is D. A 1993 study showed that teachers tend to favor males over females, thereby creating an inequality in mixed-gender schools.

Explanation:

A claim is usually a statement or phrase that expresses a strong position towards some subject, topic or situation, in this case, this position or claim is about dividing schools by gender to improve education. Additionally, for a claim to be valid the author will need to provide evidence such as examples, quotes from experts on the topic, statistics or research studies that show what the author claims have been proved by others.

Considering this, a piece of effective evidence for the claim should explain why schools in which males and females are taught together have negative effects on education or how separating males and females would benefit them. Due to this, the best evidence is D. "A 1993 study showed that teachers tend to favor males over females, thereby creating an inequality in mixed-gender schools" because it uses a research study, which is considered as a reliable source or a source that can be trusted, to explain in mixed schools there is inequality which has a negative effect on education and thus, by separating females and males the negative effect of inequality would disappear which supports the idea of improving education by diving schools by genre.

the italian poet francesco petrarch did! (: