Explanation:

For a phone-style bot that listens to customers and replies with spoken output, you use two core Azure AI Speech SDK objects:
SpeechRecognizer performs speech-to-text (STT), turning the caller's audio into text that your app can use to query the orders database. This minimizes effort because it handles audio capture/streaming, language models, and returns recognized text events/results directly.
SpeechSynthesizer performs text-to-speech (TTS), converting the retrieved order status text into natural- sounding audio to play back to the customer. It supports neural voices and simple calls like SpeakTextAsync()
.
Other options are not appropriate here:
TranslationRecognizer is for real-time speech translation, not needed for simple STT.
VoiceProfileClient is for speaker verification/identification, not for recognition or synthesis of the conversation content.
Microsoft References
Azure AI Speech SDK - Speech to text (SpeechRecognizer) overview and quickstarts.
Azure AI Speech SDK - Text to speech (SpeechSynthesizer) overview and quickstarts.
Azure AI Speech SDK concepts - recognition vs. synthesis pipelines.