How can you change the voice used in speech synthesis in Microsoft Azure?

To change the voice used in speech synthesis in Microsoft Azure, you set the SpeechSynthesisVoiceName property of the SpeechConfig object to the desired voice name. This property directly determines which voice will be utilized in the speech synthesis process, enabling you to select from a variety of voices that Azure offers.

In the context of speech synthesis, the SpeechConfig object holds critical configuration settings, and the voice name you choose can significantly affect the output's tone, accent, and overall character. Specifying the voice by name provides precise control over how the synthesized speech will sound, thus enhancing the user experience by allowing customization based on application context or user preference.

The other options, while related to the configuration of the speech synthesis feature, do not directly address changing the voice. For instance, specifying a SpeechSynthesisOutputFormat deals with the format of the audio output rather than the voice itself. Similarly, providing a filename in the AudioConfig object is about where to save the generated output, and setting the language in the SpeechConfig object is necessary for determining the linguistic characteristics but does not specify the actual voice. Therefore, option B is the most relevant and specific to changing the voice used in the speech synthesis process.