What is the correct order of ionisation energy

1.	What is the correct order of ionisation energy
Answer» `K LT CU lt Cu^(+)lt K^(+)` `K lt Cu^(+) lt Cu lt K^(+)` `Cu^(+)lt K lt Cu lt K^(+)` `K^(+)lt Cu^(+)lt Cu lt K` ANSWER :A

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