What did Hollerith's Tabulating Machine primarily use in its operation?

Hollerith's Tabulating Machine primarily operated using punch cards, which were instrumental in the processing of data during the late 19th and early 20th centuries. Punch cards, typically made of stiff paper, contained holes punched in specific patterns that represented information. This method allowed for efficient data entry and processing by using mechanical components to read the patterns of holes.

By employing punch cards, Hollerith's machine could automate the sorting and counting of data for tasks such as the U.S. Census. Each card could hold a considerable amount of information through its punched holes, and the machine could process multiple cards quickly and reliably, significantly reducing the time needed to gather and analyze data.

The other options do not align with the primary operation of Hollerith's Tabulating Machine. Magnetic tape, perforated paper, and optical scanners were developed later and did not play a role in the function of Hollerith's early data processing technology.