what is the agreement error in the following sentence:

One of the options concerning his future surgeries were discussed with him.

The agreement error in the sentence is the mismatch between the subject "One of the options" and the verb "were discussed." In this case, the subject is singular, but the verb is plural, which creates a lack of agreement in number.

To correct this agreement error, we need to ensure that the subject and the verb agree in number. In this case, since the subject "One of the options" is singular, the verb should also be singular. The corrected sentence would be:

"One of the options concerning his future surgeries was discussed with him."

Only one option WAS discussed with him.

The subject is "one," so the verb must also be singular.

I taught my students to first put parentheses around prepositional phrases. The subject, verb, and complements are never in prepositional phrases.

One (of the options) (concerning his future surgeries) were discussed (with him).