In this observational study, the company is gathering feedback from samples at food shows specifically around the state of Texas. Therefore, the results are most relevant to the population that is present and sampled in that geographic area.
The most reasonable population to generalize the results to is:
consumers in Texas
This option reflects the geographical context of the study and the demographic of the attendees who are likely to represent the opinions and preferences of consumers in that region. The other options (internationally, just San Antonio, or the entire country) are too broad or specific compared to the scope of the data collected.