X-rays are a form of electromagnetic radiation. Electromagnetic radiation consists of waves that are characterized by their wavelengths. The wavelength is the distance between two consecutive points of a wave, such as between two peaks or two troughs.

The correct answer is option 4: 10^10 (10 to the power of 10) meters. This means that the wavelength of X-rays is on the order of 10 to the power of 10 meters.

It is important to note that X-rays have very short wavelengths compared to other types of electromagnetic radiation such as visible light. X-rays have wavelengths in the range of picometers to nanometers. This short wavelength makes X-rays useful for applications such as medical imaging and material analysis.

The other options provided are not correct. Option 1, 1 meter, is far too long for X-ray wavelengths. Option 2, 10^-1 meters, is also incorrect as it is too short. Option 3, 10^-5 meters, is closer to the correct answer but still too short. Therefore, option 4 is the correct answer.