What may be indicated if a city has a common street plan but buildings use different materials?
Correct answer: A
The governing concept is to read standardisation and variation together. A common street plan suggests some degree of collective planning, regulation, or coordination, while different building materials may reflect unequal wealth, local availability of resources, imported supplies, or varied construction traditions. The evidence therefore indicates organised urban space with internal diversity. It does not prove disorder, identical building functions, or modern planning. Hence option A is correct.