When a sentence is changed from direct to indirect speech, the subject
pronoun, verbs and tense forms also change. (This is because the speech is reported by someone else, and the tense
of the direct speech goes one tense back as it's spoken at a later time
now.) The meaning of the sentence
should not be changed.
An imperative sentence, when changed to
reported speech, does not function as an imperative (command or request) anymore. It turns into
a declarative sentence.
Option B: This sentence is the correct narration of the direct speech, as
'please' has changed to 'requested' as 'please' is a form of request. 'Subbu' is in the third person, hence while changing from direct to indirect, 'me' changes to 'him'. 'This sum' changes to 'that sum'.
Hence B is correct.
Option A is incorrect because 'please' refers to polite requests whereas 'urge' refers to suggestions.
Option C is incorrect because the pronoun here 'me' has not been changed. Since the object 'Subbu' of the reporting verb 'said to' is in third person, the pronoun in the reported speech must also be in third person, i.e., 'him'.
Option D is incorrect because the answer lies in B.