Final answer:
A common source of tension between suburbs and inner city areas concerning privatization is gentrification, which can displace less affluent residents and increase living costs.
Step-by-step explanation:
In the context of urban development, a common source of tension between suburbs and inner city areas regarding privatization is C. Gentrification. This process can lead to the displacement of less affluent residents who are pushed into less desirable areas as the neighborhood's property values and cost of living increase. Gentrification often begins with individuals of lower social status investing in a neglected area and making incremental improvements. Over time, these areas become attractive to people of higher social status, which can escalate property values and living costs, making these neighborhoods unaffordable for the original residents and exacerbating social inequalities.