The correct answer is C.  The image demonstrates sporulation of the C. cayetanensis oocyst, from unsporulated phase (image 1) to sporulated  phase, which contains two sporocysts (image 3).  Each sporocyst contains two infective sporozoites that excyst and infect intestinal epithelial cells.  Oocysts of Cyclospora cayetanensis are shed unsporulated (image 1) in stools.  They require at least one week to sporulate and become infectious (image 3).  Image 2 shows an oocyst in the initial process of sporulation.

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