Email-to-Case is the feature that allows automatic case generation from incoming emails by converting emails into case records. This functionality ensures that all relevant email data is captured directly into Salesforce cases, utilizing field mapping to organize and store information correctly.

Service Cloud Einstein is designed to enhance customer service operations with AI capabilities, providing personalized, predictive, and automated interactions across all channels. This tool allows for 24/7 omnichannel support with features like AI-driven recommendations, chatbots, and automated case routing, which significantly improve the personalization and efficiency of customer interactions. Thus, "C. Service Cloud Einstein" best addresses the need for personalized 24/7 omnichannel support.
Reference: Salesforce Service Cloud Einstein

For a client needing to enable verified customers to start and continue chats only during business hours, the consultant should consider the functionalities provided by Messaging for Web and Embedded Service. Messaging for Web allows for real-time communication through the client's website, facilitating direct chat engagements. The Embedded Service provides tools to integrate this chat functionality seamlessly into the website and can be configured to recognize verified customers and enforce availability based on business hours. This combination ensures that only verified users can initiate chats during designated times, enhancing both security and user experience.
Reference: https://help.salesforce.com/s/articleView?id=sf.messaging_channels_setup_web.htm

Implementing Premier Support is the most suitable option for ongoing training and support for agents using the new Salesforce Contact Center system. Premier Support provides organizations with dedicated access to Salesforce experts and consultants who offer specialized training, proactive issue resolution, and continuous support. This level of support ensures that agents are well-equipped to use the system efficiently and can resolve any issues quickly, enhancing their overall effectiveness and comfort with the system.

Tracking customer satisfaction ratings for specific channels can be facilitated by various Salesforce features, depending on integration and automation needs:
A: Surveys triggered after case closure can be automated through case closure rules or manually initiated, fitting standard operational workflows.
B: Einstein Feedback Surveys are automatically sent based on specific interaction events, gathering timely and relevant customer feedback.
C: Custom Apex development allows for the integration of third-party survey platforms, offering flexibility and enhanced survey capabilities.
These options provide diverse methods to collect and analyze customer satisfaction across different channels, tailoring the approach to specific business needs.