The three essential types of fiber commonly used today except:
∙ A. Plastic core and cladding
∙ B. Plastic core and glass cladding
∙ C. Glass core and glass cladding (SCS)
∙ D. Glass core and plastic cladding (PCS)
∙ A. Plastic core and cladding
∙ B. Plastic core and glass cladding
∙ C. Glass core and glass cladding (SCS)
∙ D. Glass core and plastic cladding (PCS)