Development aid generally encompasses efforts to improve the economic, social, and political conditions in developing countries. Among the options provided:
B) emergency medical care - This fits within development aid, especially in the context of humanitarian assistance.
C) election observers - This can also be considered a form of development aid as it supports the democratic process and governance.
D) long-term investments - This is a core aspect of development aid, focusing on sustainable economic growth and development.
A) weapons - This does not qualify as development aid, as it does not contribute to the improvement of living conditions or development goals.
Thus, the options that would be included in development aid are B), C), and D).