Explanation

B is correct because 'Ameen-ul-Ummat' (Trust of the Ummah) is a title associated with Hazrat Abdullah R.A. A is incorrect as this title is not commonly attributed to him in this context. C is incorrect because this title refers to someone who delivers sermons, not specifically Hazrat Abdullah R.A. D is incorrect because this title generally relates to religious scholars and does not fit the historical attribution for Hazrat Abdullah R.A.