The correct answer to the question is : D) Ultraviolet rays, because they are moderate energy and abundant.
EXPLANATION;
Before going to answer this question, first we have to know the nature of electromagnetic waves.
As per electromagnetic spectrum, the gamma wave has more frequency as compared to other electromagnetic waves. After gamma wave, X-rays come. Hence, gamma ray and X-ray are more energetic as compared to others, and more harmful. They are not safe.
Radio wave has the least frequency in the periodic table. Hence, it has less energy.It is also less harmful as compared to other electromagnetic waves.
As per the option, the radio wave has high energy which is wrong.
Ultraviolet rays have moderate energy. It is harmful but not so much like X-rays and gamma rays. It is abundant as it is coming from sun.
Hence, the proper answer of this question is ultraviolet rays.
