Choose the grammatically correct sentence.

In Options A and C, ‘concerned’ precedes ‘authority’. Here, ‘concerned’  acts as an adjective. ‘Concerned authority’ means that the authority is troubled or worried. Whereas ‘authority concerned’ refers to the authority that is dealing with the issue. In the latter, ‘concerned’ acts as a past participle, modifying "authority" to mean the authority that is involved or relevant to the matter at hand. Hence, Options A and C are eliminated. In Option B, ‘report’ has been placed before ‘once’. ‘Once’ is an adverb of frequency. As per the grammar rule, adverbs of
frequency are put directly before the main verb. So, Option B can be
eliminated.

In Option D, "Concerned" in "authority concerned" acts as a past participle, modifying "authority" to mean the authority that is involved or relevant to the matter at hand.

Hence, Option D is correct.