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.
Answer:
Presente Pretérito Imperfecto
Yo hablo hablé hablaba
Tú hablas hablaste hablabas
Él / Ella / Usted habla habló hablaba
Nosotros/as hablamos hablamos hablábamos
Vosotros/as habláis hablasteis hablabais
Ellos / Ustedes hablan hablaron hablaban
Answer:
preterito is used for past actions that are completed and imperfecto is used for past actions that didn't have a start or end
examples
imperfect
repetitive action
something u used to do
time or age
talking about the future
preterito
how long it occurred
took place at a certain time
start of a event
completed actions