Answer:
c. the milling industry
Step-by-step explanation:
Milling in agriculture is defined as a process by which cereal grains are ground into flour, such as rice, wheat, corn etc.
This cereal products are farm produce which are cultivated and harvested from farming industry in in early Texas, making it, to be a need for milling factory to process them, thus leading to flour and grist milling as the first-ranking Texas industry until after the Civil War, whereby many mills of various capacities were located throughout the state.
Hence, it is correct that Milling Industry is the industry that emerged directly out of the farming industry in Texas.