challenge: What is the typical color pattern of the shell of C. articulatus?
  
  A. Solid chestnut-colored with no patterns
  B. Revolving lines of brown and yellow with a central black band
  C. Revolving lines articulated with chocolate and white, a central white band and another below the angle of the spire
  D. Horizontal stripes of blue and red with a white apex
  Answer: 