Three other missions were founded in san Antonio but were first founded in east texas. Of these is the most famous and successful in spreading spanish culture is mission?

The Alamo

Explanation:

The site known today as Alamo was the most successful mission among the first San Antonia missions. The Alamo became a large missionary complex, where Spanish Christians catechized the Indians and converted them to Christianity, often forcedly, but managed to do so with almost all the Indians in the region. Since the main objective of the missions was to convert to Christianity, this was the most successful.

In addition, this region has been promising to develop large-scale agriculture.

the answer is definitley b!