Nosotras is the correct answer
This would be something equivalent to the Town Square or The Main market, and in Spanish this would be called "Plaza".
So for example, this place in Mexico City is called Plaza de la Constitución (although it's known as Zocalo to most)
The correct way to write the sentence is;
Ustedes tienen que hablar cuando yo les pregunte algo.
o
Usted tiene que hablar y responder la pregunta que les ago.
