Answer:
B) 3rd
Explanation:
The 3rd ionization energy represents the removal of electrons from a filled core shell.
The electron configuration of calcium is [Ar]4s^2. Hence after the removal of the second electron from the 4s^2 orbital, a lot of energy is required to remove an electron from the next completely filled core shell. This is the highest successive jump in ionization energy. The other options in the question deal with electrons found on the same shell.