Which was not a feature of the post-civil war department store?
a. electricity
b. negotiation of prices
c. pneumatic tubes
d. telephones

In the Post-Civil War era, one could find many things in a department store but one thing they could not find was a. Electricity.

In the post civil-war era:

Electricity was not present at the time because it had not yet been modernized enough to allow for long distance transmission and not everyone had access to it.

In conclusion, option A is correct.

Find out more about the invention of the telephone at link.

b: the establishment clause  

b: socialism  

the correct answer is:

b) a rich merchant.