Airport security uses electromagnetic waves to see items inside of luggage without having to open the bags. Which type of electromagnetic waves would be best for airport security to use?

a
X-rays would be best because they are low-energy waves that can penetrate gases.
b
X-rays would be best because they are high-energy waves that can penetrate solids.
c
Radar waves would be best because they are low-energy waves that can penetrate gases.
d
Radar waves would be best because they are high-energy waves that can penetrate solids.

b

X-rays would be best because they are high-energy waves that can penetrate solids.