Final answer:
The correct option is 'Most popular'. Gershwin's work 'Rhapsody in Blue' is one of his most popular compositions.
Step-by-step explanation:
The correct option in the given question is b. Most popular.
George Gershwin's work, titled "Rhapsody in Blue," is considered one of his most popular compositions. It is a musical masterpiece that combines elements of classical music with jazz, and it became an instant success when it premiered in 1924.
Throughout the years, "Rhapsody in Blue" has remained a beloved piece of music and continues to be performed by musicians and orchestras worldwide.