According to the ServiceNow Hardware Asset Management documentation, a stockroom is a location where assets are stored and managed. A stockroom must have an assigned manager who is responsible for overseeing the stockroom operations and inventory. The stockroom manager must have a valid email address to receive notifications and alerts related to the stockroom, such as low stock levels, stock transfers, and stock orders.
The other options are not primary requirements for the warehouse stockroom. The stockroom does not need to have an assignment group, a valid time zone, or a valid mobile phone.

Inventory audits are the processes of verifying the accuracy and consistency of the hardware asset inventory across the enterprise1.
The Hardware Asset Management (HAM) application supports the following types of inventory audits1:
Stockroom audit: This is an audit that verifies the quantity and condition of the hardware assets in a stockroom. A stockroom is a physical location where hardware assets are stored before they are delivered to the end users or transferred to another stockroom2. A stockroom audit helps to optimize the inventory levels, avoid overstocking or understocking, and identify any discrepancies or issues with the stockroom assets1.
Location audit: This is an audit that verifies the presence and status of the hardware assets in a specific location, such as an office, a building, or a floor. A location audit helps to ensure that the hardware assets are assigned to the correct owners, locations, and departments, and to identify any missing, unknown, or unauthorized assets1.
Therefore, the types of inventory audits that are also options in the question are A. Stockroom audit and C. Location audit.
The other options that are not types of inventory audits supported by the HAM application are:
Discovery audit: This is not a type of inventory audit, but a type of configuration management activity. Configuration management is the process of maintaining the accuracy and consistency of the operational and relationship information of IT assets and services in the Configuration Management Database (CMDB)4. Discovery audit is an activity that compares the actual configuration items (CIs) in the IT environment with the expected CIs in the CMDB and identifies any differences or discrepancies4. Reference:
1: Hardware Asset Inventory Audit
2: Stockrooms
3: Vendor Management
4: Configuration Management

To utilize the contract rate cards features, you need to activate the Rate Management plugin, which provides the ability to define and manage rates for various types of costs and expenses1.
The contract rate cards features allow you to capture operating costs by generating expense lines representing the cost of a contract. You can associate a contract to certain assets and costs of those assets are tied to the contract. This is similar to a rate card cost, except the contract contains all the costs2.
The other plugins are not required to use the contract rate cards features. The Financial Management plugin provides the ability to track and manage the financial performance of your IT services3. The Contract Management plugin provides the ability to create and manage contracts for assets, services, and vendors4. The Cost Management plugin provides the ability to track and allocate costs for configuration items, tasks, and projects5. References: 1: Rate Management 2: Cost Management - ServiceNow Elite 3: Financial Management 4: Contract Management 5: Cost Management

The Service Catalog provides a user-friendly interface for requesting hardware assets and services from the IT department1 The Service Catalog facilitates the ability to source from existing stock by allowing users to select from a list of available hardware products that are in stock or reserved in a stockroom2 The Service Catalog also enables users to view the status of their requests, track the delivery and return of assets, and report any issues or incidents related to assets1 The Service Catalog is integrated with the Procurement Catalog, which contains the list of hardware products that are currently on order or have been received from vendors3 The Service Catalog is also linked to the Product Catalog, which contains the list of hardware products that are available for purchase from vendors or internal sources4 The Vendor Catalog contains the list of vendors that supply hardware products, but it does not facilitate the ability to source from existing stock