According to the ServiceNow Hardware Asset Management documentation, original cost is the amount paid to acquire an asset, including any taxes, fees, shipping, installation, or other expenses directly related to the purchase. Original cost is used to calculate depreciation and amortization of an asset over its useful life. The other options are not the type of cost that taxes paid at the time of purchase are. Operating expense, operating cost, and capital expense are different ways of classifying the costs of using and maintaining an asset after it is purchased.

Explanation
According to the ServiceNow Hardware Asset Management documents, the default display name for an asset is an automatically generated combination of asset tag and model1. The asset tag is a unique identifier for the asset, and the model is the name of the hardware or consumable model that the asset belongs to2. The other options are not correct, as they do not match the default display name format. The serial number is another unique identifier for the asset, but it is not used in the display name by default2. The model category is a classification of the model based on its type, such as laptop, printer, or monitor3, but it is also not used in the display name by default. References:
Asset fields for enterprise assets
Hardware Asset Management overview
Hardware Asset Management landing page

Normalization is the process of restructuring data to maintain consistency, accuracy, and completeness across different sources and systems. Normalization helps to eliminate data duplication, conflicts, and errors, and to ensure that the data conforms to predefined standards and rules. Normalization is especially important for hardware asset management, as it enables users to have a clear and unified view of their hardware models, manufacturers, product names, device types, and other attributes. ServiceNow Hardware Asset Management provides a feature called Hardware Model Normalization, which allows users to normalize the details of their hardware and consumable models using predefined or custom rules, data sources, and schedules. Hardware Model Normalization can be accessed from the Hardware Asset Management application menu in the ServiceNow platform1. Reference: Hardware Asset Management - ServiceNow, Hardware Asset Management - Product Documentation: Tokyo - ServiceNow, Hardware Asset Management Implement - Customer Success - ServiceNow, Work with hardware normalization - ServiceNow - Now Support, Getting Started with ServiceNow Hardware Asset Management