Explanation

A is correct because Lt Gen (retd) Nasser Khan Janjua resigned as NSA on that date. B is incorrect because Sartaj Aziz held a different role or was not the one who resigned on this specific date. C is incorrect because Tarique Aziz is not associated with resigning from the NSA post on June 27, 2018. D is incorrect because option A names the correct person who resigned.