A logo design featuring the letter "C" in a circular shape could include a simple yet elegant design. The letter "C" could be illustrated in a bold font, with the circular shape surrounding it. The letter "C" could be the focal point of the design, and the circle could be used to emphasize its shape. The design could be monochrome or feature a color scheme that complements the letter "C", like using a gradient or multiple colors. The overall design should be minimalistic and easy to read while still capturing the essence of the brand it represents. You can also include additional design elements such as a symbol or icon within the circle to make it more meaningful and unique.