Who has the authority to form municipal corporations in Arizona?

The authority to form municipal corporations in Arizona is vested in the legislature. This is based on the state's constitution and statutory provisions that outline the process for the creation of municipalities. The legislature has the power to create laws that can establish cities and towns, taking into account factors such as population, geographic boundaries, and community needs.

Counties, while they play a role in local governance, do not have the authority to create municipalities independently. The governor does not have direct authority over the formation of municipal corporations, as that power is legislative in nature. Civic groups can advocate for the creation of a municipality but do not possess the legal authority to establish one independently. Thus, the correct answer highlights the necessary legislative process for the formation of municipal corporations in Arizona.