The OCR marks option A (1.3 µm) as the answer; some LEDs (especially infrared) emit around 1.3 µm, matching the marked option.

Sound waves are mechanical longitudinal waves and are not part of the electromagnetic spectrum.

X-rays are a form of electromagnetic radiation, not particles like electrons or nuclei.

For equal wavelength (h/λ), momentum is equal; KE = p^2/(2m) so the electron (smaller mass) has larger kinetic energy than the proton.

Thermal radiation propagates as electromagnetic radiation and travels at the speed of light in a vacuum.

The photon is the quantum (elementary particle) of electromagnetic radiation, carrying energy proportional to its frequency.

Microwave ovens commonly operate at about 2450 MHz (often listed as 2450), matching the option marked in the OCR.

When radiation occurs only at specific discrete values (lines), it is called a discrete spectrum.

Photons are massless quantum particles of light, so 'has no mass' correctly describes a photon.

LASER light is typically monochromatic, coherent and can be very intense, so all listed properties apply.