Explanation
Benefits of SaaS
The main benefit of SaaS is that it offloads all infrastructure and application management to the SaaS vendor.
Reference: https://www.ibm.com/cloud/learn/iaas-paas-saas

Features of Cloud Spanner
Reference:

The correct answer is C. Firewall rules. Here's why:
* Context of the Question: The organization wants to control what types of network traffic are allowed to enter and leave its network and access its applications.
* Google Cloud Product Relevance:
* Firewall rules are security settings used to control the flow of traffic to and from instances or resources in a network. They define which traffic is allowed or denied based on parameters such as IP address, protocol, and port.
* Firewall rules are essential for protecting applications from unauthorized access and for ensuring that only trusted traffic is permitted.
* Why Not Other Options:
* A. Encryption keys: Encryption keys are used for data protection and encryption but do not control network traffic.
* B. 2-Step Verification: This enhances account security by requiring a second form of authentication but does not control network traffic.
* D. Privileged access: This refers to managing access rights for administrative tasks and is not related to controlling network traffic.
Google Cloud Digital Leader References:
* Refer to Google Cloud VPC firewall documentation to understand how firewall rules are used to control network traffic.

Explanation
Legacy infrastructure is typically based on on-premises hardware that is managed and maintained by the organization. As the application grows and the user base expands, the hardware required to support it must also grow. This can lead to significant costs associated with provisioning and maintaining hardware, particularly if the organization needs to provision for peak usage.