Final answer:
Jose de Escandon played a crucial role in developing southern Texas through the establishment of towns and missions, expanding New Spain's presence in the area. Option b. is the correct answer.
Step-by-step explanation:
Jose de Escandon significantly affected the expansion of New Spain by working diligently to establish many towns and missions in southern Texas. His work helped to increase the non-Native population in the region, creating a buffer zone against both native tribes and potential American expansion. By bringing settlers as part of Spain's empresario system, Escandon contributed to the wider Spanish effort to populate and develop their New World territories, which had previously been limited due to challenging conditions and reluctance from potential European settlers.