The basic rules in punctuating a sentence are that we use a full stop for a declarative sentence, a question mark for an interrogative sentence and an exclamation mark for an exclamatory sentence. Further, a comma is used to indicate the separation of ideas or elements. In the given sentence the speaker enquires about the listener's well being. Thus it is an interrogative sentence that indicates a question. Therefore it needs to be punctuated with a question mark, so option C is correct. Whereas a full stop or exclamation mark cannot be used since it is not a declarative or exclamatory sentence. Hence options A and B are incorrect. Similarly, the sentence doesn’t convey multiple ideas and only poses a question. So a comma cannot be used to punctuate the sentence. Hence option D is incorrect.