The correct answer is D. Readers' Guide.
Explanation: While many believe that you would need to look through books on fashion design, it does not specify trends from the 1980s. The most efficient way to research fashion trends from the past is by using the Reader's Guide. The Reader's Guide is a reference guide for periodical magazines, published articles, and scholarly journals. It is organized by article subject and it traces magazine articles from 1901 to present.