Which IBM Watson service is used for text analytics that detects sentiment and emotion?

The correct choice is the service designed for text analytics that specializes in detecting sentiment and emotion, which is Natural Language Understanding. This service utilizes advanced natural language processing techniques to analyze the sentiments expressed in text. It can identify positive, negative, or neutral sentiments, as well as specific emotional tones such as joy, anger, or sadness. This capability allows businesses to gain insights into customer perceptions, preferences, and reactions by processing and understanding language in a much deeper way.

Natural Language Understanding is integral for applications where sentiment analysis is crucial, such as social media monitoring, customer feedback analysis, and brand reputation management. It goes beyond mere topic detection, providing comprehensive insights into the feelings and attitudes conveyed in the text.

While Personality Insights is focused on deriving personality characteristics from text data, it does not directly assess sentiment or emotion in the same manner as Natural Language Understanding. Facial Recognition, on the other hand, deals with visual data and does not analyze textual inputs at all, and the Natural Language Classifier is designed primarily for categorizing text rather than determining sentiment. Thus, Natural Language Understanding is the ideal choice for sentiment and emotion detection in text analytics.