Final answer:
Towns in the Maxwell Land Grant in New Mexico were developed largely due to the construction of railroad lines, which facilitated industrialization and business growth, transforming small towns into urban centers. The correct option is C.
Step-by-step explanation:
Towns developed in the Maxwell Land Grant in New Mexico significantly through the construction of railroad lines. By the late nineteenth century, industrialization had increased the economic size of the United States, which, along with the growth of railroad infrastructure, promoted urban development and federal centralization.
The government's involvement in providing land to railways encouraged this movement and set the stage for the regulatory framework of the early twentieth century. These changes played a critical role in shaping the West, with mining and cattle industries transitioning from individual to business enterprises and subsequently building up small towns into thriving cities.
Hence, Option C is correct.