which type of radiation travels at the speed of light and penetrates matter easily?\no beta particles\no…

Answer:

D. gamma rays

Brief Explanations:

Gamma - rays are electromagnetic radiation and travel at light - speed. They have high energy and can penetrate matter easily. Beta particles are electrons or positrons with lower penetration power. Radionuclides are radioactive atoms, not a type of radiation. Alpha particles are helium nuclei with low penetration ability.