The correct option is
C Ciliated cells
The testis is the primary sex organ whose function is to produce sperms. However, only 60% sperms produced by the testis are normal. The rest 40% are abnormal with impaired shape and motility. So, the vasa efferentia has ciliated epithelium to prevent these abnormal sperms from moving into the ejaculate.
So the correct answer is C.