The correct completion of the sentence is:

“The interactive answering of questions entered by a user as part of an application is an example of natural language processing.”

According to the Microsoft Azure AI Fundamentals (AI-900) official study materials, Natural Language Processing (NLP) is a branch of Artificial Intelligence that focuses on enabling computers to understand, interpret, and respond to human language in a way that is both meaningful and useful. It is one of the key AI workloads described in the “Describe features of common AI workloads” module on Microsoft Learn.

When a user types a question into an application and the system responds interactively — such as in a chatbot, Q & A system, or virtual assistant — this process requires language understanding. NLP allows the system to process the input text, determine user intent, extract relevant entities, and generate an appropriate response. This is the foundational capability behind services such as Azure Cognitive Service for Language, Language Understanding (LUIS), and QnA Maker (now integrated as Question Answering in the Language service).

Microsoft’s study guide explains that NLP workloads include the following key scenarios:

Language understanding: Determining intent and context from text or speech.

Text analytics: Extracting meaning, key phrases, sentiment, or named entities.

Conversational AI: Powering bots and virtual agents to interact using natural language.These systems rely on NLP models to analyze user inputs and respond accordingly.

In contrast:

Anomaly detection identifies data irregularities.

Computer vision analyzes images or video.

Forecasting predicts future values based on historical data.

Therefore, based on the AI-900 official materials, the interactive answering of user questions through an application clearly falls under Natural Language Processing (NLP).