Which service is designed to provide voice interactions as part of a customer service solution?

AWS Lex is specifically designed to facilitate voice interactions as part of a customer service solution. It is a service for building conversational interfaces using voice and text. Lex leverages deep learning technologies to enable natural language understanding (NLU) and automatic speech recognition (ASR), allowing developers to create applications that can interact with users through voice and text chat.

In the context of a customer service solution, AWS Lex can be employed to build chatbots that assist customers by providing automated responses to inquiries, guiding users through processes, or even allowing them to complete transactions. The integration of voice functionality enriches the user experience by making interactions more intuitive and accessible.

Other options, while valuable in their respective domains, do not focus on providing voice interactions. For instance, AWS QuickSight is primarily a business analytics service for data visualization, AWS Glue is an ETL (Extract, Transform, Load) service for preparing data for analytics, and AWS MSK is a managed streaming service for Kafka that helps in building data streaming applications. These services do not cater to voice interaction capabilities, highlighting why AWS Lex is the correct choice for this question.