The correct verb to fill in the blank is are.
Here's why:
When you have "either... or..." as the subject of a sentence, the verb agrees with the noun or pronoun closer to the verb. In this case, "sisters" is plural and is closer to the blank, so the verb should be plural ("are").
اذا كان لديك إجابة افضل او هناك خطأ في الإجابة علي سؤال Either my brother or my sisters ....... going to tutor me in math اترك تعليق فورآ.