Which of the following teaching-learning resources in mathematics cannot be…

Teaching-learning resources (TLRs) for visually challenged learners need to remain usable without relying on sight - through touch, sound, or braille - so that they are accessible in an ordinary classroom that has not been given individualised assistive adaptation for the resource.

Among the given options, GeoGebra is dynamic mathematics software whose graphs, constructions, and their changes are displayed only on a computer or tablet screen; without a specific accessibility adaptation such as audio description or a tactile-graphics interface, its content cannot be accessed through touch or sound alone, so it fails the sight-independence requirement in an ordinary classroom setting.

• Taylor's abacus is a calculating frame that a student sets and reads by touch, so it remains usable without relying on sight.

• Tiles are physical pieces that a student can feel and arrange by hand, so they remain usable without relying on sight.

• A GeoBoard is a physical pegboard on which a student stretches rubber bands and feels the resulting shape, so it remains usable without relying on sight.

Because Taylor's abacus, tiles, and the GeoBoard remain usable without relying on sight, while GeoGebra's content is accessible only through visual observation of a screen without additional adaptation, GeoGebra is the resource that cannot be used for visually challenged students in an ordinary, unadapted classroom.