I believe The answer is B. Hope this Helps :)
The appropriate choice for the non-event is ...
... A. The costs of sewing machines began to increase.
_____
Interchangeable parts generally reduce costs and increase demand (and production).
DescriptionLos Angeles is a sprawling Southern California city and the center of the nation’s film and television industry. Near its iconic Hollywood sign, studios such as Paramount Pictures, Universal and Warner Brothers offer behind-the-scenes tours. On Hollywood Boulevard, TCL Chinese Theatre displays celebrities’ hand- and footprints, the Walk of Fame honors thousands of luminaries and vendors sell maps to stars’ homes.
