The correct option is D were discussing/were talking
The word 'while' explains that the actions in the given sentences are in continuous tenses.
Option A - 'Discuss/talk' are in the original verb forms. Thus option A is incorrect.
Option B - 'Are discussing/was talking' is incorrect. The word 'while' explains that the actions took place at the same time and hence we can't use different tenses in one sentence here. Thus option B is incorrect.
Option C - 'Being discussed/Being talked' is incorrect. As the given sentence is in the active voice, we can't use 'being', as 'being' is used in the passive voice. Thus option C is incorrect.
Option E - 'Have discussed/have talked' is incorrect as it is in the present perfect tense. Thus option E is incorrect.
Option D - 'Were discussing/were talking' are both in the past continuous tense and hence we can use 'were'. Thus option D is the correct answer.
'While the gentlemen were discussing the recent events, the ladies were talking about the weather.'