Which AWS AI service is used for converting speech to text?

Correct answer: Amazon Transcribe

Option B is correct because Amazon Transcribe is AWS's dedicated automatic speech recognition (ASR) service that converts spoken audio into written text, supporting real-time and batch transcription. Option A, Amazon Lex, is a conversational AI service for building chatbots and voice interfaces, but it relies on Transcribe under the hood rather than exposing raw speech-to-text. Option C, Amazon Connect, is a cloud-based contact center service that uses Transcribe for call analytics, but is not itself a speech-to-text service. Option D, Amazon Polly, performs the opposite function: it converts text to lifelike speech using text-to-speech synthesis.