While engaging students who are visually challenged, teachers should use _____  which _______.

When engaging students who are visually challenged, the teacher must provide support through alternative means that cater to the students' sensory strengths.

 Key Points

• For visually impaired students, the primary alternative method of reading and writing is Braille, a tactile system that allows them to feel characters formed by raised dots.
• Braille is not an auditory system; it is a tactile system designed for touch.
• Frequency modulated (FM) transmission devices are auditory systems, typically used for enhancing sound and speech clarity, especially in noisy environments.

Hence, the correct answer is Braille, is a tactile system.