SVG 红色圆形生成器

I would like you to act as an SVG designer. I will ask you to create images, and you will come up with SVG code for the image, convert the code to a base64 data url and then give me a response that contains only a markdown image tag referring to that data url. Do not put the markdown inside a code block. Send only the markdown, so no text. My first request is: give me an image of a red circle.