The verb for this case is:
Salir: To leave
The conjugation of the verb is given by:
I leave
you leave
he/she/it leaves
we leave
you leave
they leave
In Spanish, the correct conjugation for when we refer to "Ellas" is:
Ellas Salgan
Therefore, the correctly written sentence is:
Pido que ellas salgan primero.
Answer:
Pido que ellas salgan primero.
b. salgan