To be designated as an urban center, a community must have a population of at least:

To qualify as an urban center, a community must meet a specific population threshold that aligns with state planning goals and definitions. The requirement of a minimum population of 40,000 is significant because it reflects the intention to recognize urban centers as areas with a certain level of density, infrastructure, and economic activity that can support urban development initiatives.

Choosing the population mark of 40,000 indicates that the community is large enough to sustain urban characteristics, such as diverse services, infrastructure capacity, and opportunities for economic growth. This designation is important for planning purposes, allowing for better allocation of resources and implementation of policies geared toward urban centers, which are often focal points for regional growth and development.

The other population thresholds provided in the options are too low to meet the criteria for being designated as an urban center based on New Jersey's planning laws. They pertain to different planning designations or community types that do not reflect the same level of urbanization. Thus, the correct choice emphasizes the state's focus on substantial community size for urban center designation, allowing for effective planning and development tailored to urban settings.