The answer is: Constituents are more directly affected by domestic policy topics than foreign ones.
This option is not entirely accurate. While some legislators may have less interest in foreign policy, many are indeed interested and involved in these issues, especially those on relevant committees. However, their level of activity is often influenced by other factors.
While legislators may consider the views of immigrant groups, this is not a primary reason for their relative inactivity in foreign policy. Domestic issues tend to have a more immediate impact on their constituents' daily lives, which is a more significant factor.
This is the most accurate explanation. Legislators prioritize issues that have a direct and immediate impact on their constituents' lives, such as healthcare, education, and infrastructure. These domestic issues are often more pressing for voters, influencing legislators to focus their efforts accordingly.
While foreign policy can indeed be complex, this alone does not account for the lower level of legislative activity. Legislators often rely on experts and advisors to navigate technical issues, whether domestic or foreign. The primary reason remains the direct impact of domestic policies on constituents.