Final answer:
The iconic fashion trend emphasizing an hourglass shape for women in the 1890s was The Gibson Girl look. It contrasts the 1920s Flapper style that de-emphasized the female form with straight lines.
Step-by-step explanation:
The iconic fashion trend that became popular in the 1890s and emphasized an hourglass shape for women was a) The Gibson Girl look. This style was characterized by a tightly corseted waist which flared out into a voluminous skirt, creating a dramatic hourglass silhouette. In contrast, the Flapper style, which became popular in the 1920s, was known for its straight lines that de-emphasized the female form, with knee-length skirts, dropped waistlines, and bobbed haircuts. This represented a departure from the Gibson Girl as it reflected the rebellious and liberated spirit of the Jazz Age, along with the broader women's rights movement.