Reading Comprehension: Detail Function Questions
The author's discussion of movie stars is meant to
The key to this question is the phrase build on. It indicates that De Beers' used movie stars to promote a certain idea about its product, or in other words, as a marketing strategy.
Although this answer choice makes sense, it does not agree with the information given in the passage. The passage tells us that movie stars promoted the idea of diamonds as an expression of romance and not as a symbol of prestige.
Be careful of applying your own general knowledge when answering Reading Comprehension questions. Instead, always stick to information which appears in the passage.
The author does not mention movie stars to show how successful the advertising was eventually. The movie stars had a specific role in the advertisement campaign, so the author must mention them to show how they contributed to the following success.
The passage states that movie stars were used in De Beers' commercials to sell diamonds; the author does not refer to them as the target audience of the advertising.
Although movie stars did play a role in De Beers' advertising, they were not a failure but a success.