from The California Gold Rush

What does the phrase like gasoline on a fire in paragraph 1 most clearly emphasize in the passage?

1 At a time when restless Americans were already itching to go west, the discovery of gold in California in 1848 was like gasoline on a fire. Within a year of its discovery, emigrants using the California Trail were flooding into the Sierra Nevada Range by the thousands.

2 Many who already had arrived in California or Oregon immediately gravitated to the western Sierras. But it wasn't until December of 1848 that President James Polk confirmed the findings to Congress, which meant it was too late to start a trip for easterners. But by the spring of 1849, the largest migration (25,000 that year alone) in American history was already taking place.

(from "The California Gold Rush" by National Park Service)

1. the wild excitement of becoming rich in California

2. the intense hope of starting a new life in California

3. the dramatic surge in people traveling to California

4. the real danger associated with the trip to California

3. the dramatic surge in people traveling to California