Different parts of the electromagnetic spectrum are used for different purposes. Below are four statements about parts of the spectrum. statement 1: Infra-red waves are used in television remote controllers. statement 2: Radio waves are used to transmit television pictures from satellites to Earth. statement 3: Ultra-violet waves are used for intruder alarms. statement 4: X-rays are used for security checks. Which statements are correct?

• A1 and 2
• B1 and 4
• C2 and 3
• D3 and 4

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