Final answer:
Gamma rays have a wavelength range shorter than 10 trillionths of a meter and are more energetic than visible light, X-rays, and ultraviolet radiation. They are on the high-energy end of the electromagnetic spectrum.
Step-by-step explanation:
Electromagnetic radiation with a wavelength shorter than 10 trillionths of a meter (10^-12m) corresponds to gamma rays. Gamma rays are on the far end of the electromagnetic spectrum and possess even shorter wavelengths than X-rays and ultraviolet radiation. While X-rays have wavelengths between 0.01 nanometer (10^-9m) and 20 nanometers, gamma rays can have wavelengths as short as 10^-16 meters, making them one of the highest-energy forms of electromagnetic radiation.
Comparing with visible light, which has wavelengths in the range of 400 - 700 nm (nanometers, or 10^-9 meters), gamma rays have much shorter wavelengths and are far more energetic. This high energy allows gamma rays to be highly penetrating, making them useful in medical applications such as cancer treatment but also dangerous to living tissues. The correct answer to the question is therefore d. Gamma rays.