Final answer:
The invention that helped department store owners manage sales records and deter employee theft in the late 19th century was the cash register, which was essential in the era of burgeoning department stores and consumer culture.
Step-by-step explanation:
The invention of the cash register addressed two challenges faced by department store owners in the late 19th century: creating detailed sales records and preventing embezzlement by employees. The department store phenomenon, exemplified by places like the Bon Marché in Paris and Wanamaker's in Philadelphia, revolutionized retail by offering a wide variety of goods, attractive displays, and fixed pricing. To manage the increasing volume of transactions and protect their revenues from dishonest practices, store owners needed an efficient way to record sales and track cash flow. The cash register, introduced in the late 1800s, solved these problems by recording each transaction and providing owners with a method to account for all cash handled during the day, thereby deterring theft by employees.