What was a common purpose of missions and presidios established in the 1690s?

The establishment of missions and presidios in the 1690s primarily aimed to convert Indigenous peoples to Catholicism while also providing military protection. During this period, Spanish colonial authorities sought to expand their influence in the New World, and the missions served as religious outposts meant to evangelize Native populations. By integrating religious instruction with European cultural practices, the missions sought to instill the Catholic faith among Indigenous communities.

Simultaneously, presidios were military forts built to protect these missions and the surrounding area from potential threats, such as rival European powers or hostile Indigenous groups. The dual purpose of conversion and protection was foundational to Spain’s strategy for maintaining control over its territories in the Americas, facilitating not only spiritual but also political stability.

The other options reflect different objectives that were not the primary focus during this era. While trade and agricultural advancements were important for colonial development, they were secondary to the mission's dual role of religious conversion and military defense. Promoting migration from Europe also occurred but was not the central aim of missions and presidios specifically in the context of the 1690s. Thus, the combination of religious and protective functions distinguishes choice B as the most accurate answer.