Based on modifies the subject of the main clause of the sentence.

What specific question was the most popular on the ACT test?

My subject is based on the test scores that the questionor provided above and it is wrong. Is this true? Why? On the basis of the

test scores, Scott selected the top candidates in his field.

Scott

selected the top candidates on the basis of their test scores.

On the basis of modifies the main verb of the sentence “Verseman” as it has been to the end of the sentence.

Scott chose the top candidates who would run for his position on the merits.

The quiz scores were used in the selection process.