Step 1: Identifying the correct option:
MacIver, who gave the classic definition of community, identified "we-feeling" (a shared sense of belonging and identity among members living in a common area) as the defining sentiment that binds a community together.
Step 2: Why the other options are wrong:
Primary group, family and marriage are all specific social institutions/groups in their own right, not the defining sentiment of community itself - a community is a broader entity that contains many such groups.
Final Answer:
We feeling (Option B)