The correct option is A in
Option A- 'in' is the most suitable preposition to complete the word. 'In' highlights a specific location or a place. Here in the above-given sentence, there is a mention of the article which is present in the paper (it is printed in the newspaper). 'On' describes something present on the surface of an object. 'At' generally highlights a specific time or an activity. Hence, 'on' and 'at' cannot be used to complete the sentence. 'For' cannot be an appropriate word to complete the blank as it highlights the use of something. Hence options B, C and D are incorrect.