The correct option is C stringent
Option C: 'Stringent' is an adjective that means 'strict, firm, rigid'. It is relevant to the meaning of the sentence, thereby completing it: 'the announcement was made as part of strict measures...' Hence option C is correct.
Option A: 'Inconspicuous' is an adjective that means 'not clearly visible or attracting attention'. It does not seem relevant to the sentence, as the word 'announcement' negates that 'the measures would not attract attention'. Hence A is incorrect.
Option B: Similarly, 'moderate' is an adjective that means 'average in intensity'. The word does not agree with the meaning of the given sentence sentence, 'moderate' measures and the 'announcement that was made' don't go together. Hence B is incorrect.
Option D: 'Statute' is a noun that refers to 'a written law passed by a legislative body'. It's a noun itself and hence cannot modify another noun "measures". Also, the meaning 'laws and regulations' does not apply to the sentence. Hence D is incorrect.