Hi, Dr. Sharma, this is Siddharth from your Gp. 3 weekend AP Chem class. I was reviewing some old quizzes and I found this problem:

Could you please explain why this is the correct answer?

3.11 Spectroscopy & Electromagnetic Spectrum
Please check notes on this topic.
IR radiations are responsible for vibrational motion of chemical bonds and types of bonds decide the frequency of stretching or bending of bonds. This frequency helps in identifying the type of the bond as each different type of bond has different strength so different frequency.