Answer:
a.
Explanation:
I believe the full question is "Artists captured the transformation of urban landscapes in the Progressive era through all of the following EXCEPT:". This being the case the exception to this would be photographs of theaters. This is because the Progressive era for artists was a focus on emphasizing problems that have been brought on by corruption, urbanization, industrialization and immigration. All of the answers provided have an attachment to these problem categories except for theaters that were mainly for the rich and sophisticated in that era.
