The correct option is option B (Natural language). RPA (Robotic Method Automation) answers to customers in linguistic communication instead of software code by implementing machine learning, computer code or online machine assistants for voice recognition. RPA will answer to queries in natural language employees or customers by facilitating machine learning or promoting online machine assistants for the purpose of voice recognition.
If you are interested to learn RPA, I recommend this RPA training by Intellipaat that covers all the above topics.
You can watch this video on Robotic Process Automation to learn basics of RPA: