Two Different Electron Beams Are Incident on Two Different Targets

Multiple Choice

Two different electron beams are incident on two different targets and both produce x rays.The cutoff wavelength for target 1 is shorter than the cutoff wavelength for target 2.We can conclude that:

A) target 2 has a higher atomic number than target 1
B) target 2 has a lower atomic number than target 1
C) the electrons in beam 1 have greater kinetic energy than those in beam 2
D) the electrons in beam 1 have less kinetic energy than those in beam 2
E) target 1 is thicker than target 2