Step 1: Understanding urban problems.
Urban problems arise due to rapid urbanization and population growth in cities. These lead to issues such as pollution, shortage of resources, and poor living conditions.
Step 2: Analyzing the options.
(A) Air pollution: Common in urban areas due to vehicles, industries, and construction.
(B) Scarcity of drinking water: Overpopulation and poor management often lead to water shortages.
(C) Slum: Unplanned settlements or slums are major urban issues caused by migration and poverty.
(D) All of these: Since all the above are major urban problems, this is the correct option.
Step 3: Conclusion.
The correct answer is (D) All of these, as all listed options are significant urban problems.