The elements argon, potassium, and calcium are consecutive in the periodic table. Which gives the correct order of increasing first ionization energies?

A.     ${\text{Ar}} < {\text{Ca}} < {\text{K}}$

B.     ${\text{K}} < {\text{Ar}} < {\text{Ca}}$

C.     ${\text{Ca}} < {\text{K}} < {\text{Ar}}$

D.     ${\text{K}} < {\text{Ca}} < {\text{Ar}}$

D

The most common wrong answer was C.