I believe your answer is number 2.
Correct me if I am wrong. :)
Answer: Clear
Explanation: prepositions are limited in number, they are important especially in a sentence because they act as vital markers to the structure of a sentence making the sentence clear.
The purpose of the advertisements is to sell the products to the customers. Using survey, advertisers develop insight about this. The advertisement does not always provide product details. Indeed, the concept of the product details is the result of the survey, but it does not mean that the concept has to be shown in the advertisement.
Options A and D are very close answers to the question. Catchy slogan does not add exact persuasiveness to the advertisement. Indeed, persuasive advertisement for the product shows the product for the needs of the customers. Therefore, the correct answer is D.
