Which type of fiber-optic cable is the most widely used?
∙ A. single-mode step-index
∙ B. multimode step-index
∙ C. single-mode graded index
∙ D. multimode graded index
∙ A. single-mode step-index
∙ B. multimode step-index
∙ C. single-mode graded index
∙ D. multimode graded index