Step 1: Understanding the Meaning of 'Urban': 
  
'Urban' refers to anything related to cities or towns. The opposite of urban would relate to rural or countryside areas. 
Step 2: Analyzing the Options: 
- Rustic: This is a good option because "rustic" refers to something related to the countryside, which is the opposite of urban. 
  
- Rural: The correct antonym of "urban," as "rural" refers to areas outside of cities, often characterized by fewer people and more open spaces. 
  
- Civil: Incorrect, as "civil" refers to polite or societal behavior, which does not contrast with "urban." 
  
- Foreign: Incorrect, as "foreign" refers to something from another country, not the opposite of "urban." 
Step 3: Conclusion: 
  
The correct antonym of "urban" is rural, which refers to the countryside.