Explanation

The historical record does not clearly state that Hazart Abdullah Bin Masud (R.A) was appointed as the custodian of bait-ul-mal by Hazrat Umar (R.A). Option B is incorrect because it names a different person and relationship to Umar (R.A). Option C is incorrect because it names a different individual. Option D is correct because based on available historical texts, none of the specific options listed are definitively recorded as the appointed custodian.