With expressions such as 'es raro que' you need to use the subjunctive form of a verb which is slightly different than the present, indicative form. So, the 'normal' form of ir for third person plural would be van. However, we need the subjunctive form here, which is vayan.
This means that the correct answer is A. Vayan a la escuela los sabados.
The form ven doesn't exist.
ir
i dont understand the difference between the first and second one
Brillaba como el necklace era mi best friend no se lo que siente yo soy el de siempre