The timeline implies that Rosa Parks was a civil rights activist before her arrest on the bus. This can be inferred from her prior involvement in civil rights organizations and her understanding of the broader context of racial segregation and discrimination. Her act of defiance on the bus was not a spontaneous decision; rather, it was a calculated move within the framework of her ongoing commitment to civil rights. Therefore, the best response from the options provided is:
Rosa Parks was a civil rights activist before she was arrested off the bus.