The correct answer is Option C. A diary entry is generally written to record one's feelings, emotions and thoughts on an incident related to the writer or to record an event important to the writer.
Option A is incorrect as a poster is generally used to advertise or promote eye-catching facts or products.
Option B is incorrect as a headline generally gives us a quick overview of an article or a piece.
Option D is incorrect as an advertisement is used to inform the consumers about the product or services of a company.