If you need to send emails to the creative team for proofing as part of an email campaign, you should use Approval Workflow as an automatic flow. This feature allows you to create approval rules and assign approvers for your emails before they are sent. You can also track the status of your approvals and receive notifications when they are completed or rejected. Subscriber Preview is a tool that allows you to preview how your email will look for different subscribers, but it does not send them an email. Content Builder Approvals is a feature that allows you to request feedback on your content from other users within Content Builder, but it does not send them an email either. You can learn more about this in the [Email Approval Process] module on Trailhead.

Automation Notification Settings allow marketers to configure email notifications for automation activities, such as data imports, data exports, or SQL queries. Marketers can choose to receive notifications for all activities, only failed activities, or none. [Source: Trailhead]

Data Designer is the tool that should be used to create a sendable data extension from various tables including orders, subscribers, and product line items. Data Designer allows you to create custom data extensions that can be used as an entry source for a journey. It also allows you to join multiple data sources together to create a single data extension. You can find more information about Data Designer and how to use it here: Data Designer. Automation Studio is a tool that allows you to automate tasks such as sending emails, importing files, extracting data, etc. Audience Studio is a tool that allows you to collect and unify data from various sources and create audience segments for personalized marketing.

Implementing an SAP with Private Domain and a Dedicated IP is the best action to ensure NTO's sending reputation remains intact, as it allows NTO to have full control over its sender authentication and IP reputation. A private domain enables SPF and DKIM authentication, which helps to verify the sender's identity and prevent spoofing. A dedicated IP isolates NTO's sending volume and reputation from other customers, which reduces the risk of being affected by their sending practices. Requesting three dedicated IPs or a private domain alone would not provide the same level of protection as an SAP.

The configuration that should help with limiting a spike in volume to the website is Send Throttle1. Send Throttle allows you to specify the number of emails to send per hour, which can help you control the traffic to your website and avoid overwhelming your server or exceeding your bandwidth limit2. By using Send Throttle, you can also improve your email deliverability and avoid being flagged as spam by ISPs that monitor sudden spikes in email volume3.
Sender Authentication Package is not the correct answer, as it does not help with limiting a spike in volume to the website. Sender Authentication Package is a feature that helps you authenticate your email sender identity and domain, which can improve your email reputation and deliverability4. However, it does not affect the rate or timing of your email sends.
Web Collect Sign-Up Form is also not the correct answer, as it does not help with limiting a spike in volume to the website. Web Collect Sign-Up Form is a feature that helps you collect email subscribers from your website, which can increase your email list size and engagement. However, it does not affect the rate or timing of your email sends. References := 1: Send Throttle - Salesforce 2: Marketing Cloud Email Specialist Certification Guide & Tips 3: Email limitations in marketing cloud - Salesforce Developer Community 4:
Sender Authentication Package - Salesforce : Web Collect Code Samples - Salesforce