Which of the following combination(s) is/are NOT correct?

Teaching aids are classified by the sense(s) through which they deliver information: audio aids use sound only, visual aids use sight only, and audio-visual aids combine sound with moving images at the same time.

Applying this test to each pairing: cassette recordings and radio broadcasts are heard, not seen, so both correctly pair with "audio aid." Graphs are seen, not heard, so pairing graphs with "visual aid" is also correct. Television broadcasts, however, carry synchronized sound together with moving pictures, so the sense-channel test places television under "audio-visual aid," not under "visual aid" alone.

• Cassette – Audio aid: correct, a sound-only channel.

• Graphs – Visual aid: correct, a sight-only channel.

• Television – Visual aid: incorrect; television carries sound and moving pictures together, so labelling it a plain visual aid leaves out its audio channel.

• Radio broadcasts – Audio aid: correct, a sound-only channel.

Cross-check: removing either the audio or the video component from a television broadcast would lose information the medium is designed to carry, confirming it belongs to the combined audio-visual category and cannot be filed under "visual" alone.

So the combination that is NOT correct is Television – Visual aid.