It can be inferred from this graphic that the events of the 1850s resulted in

1. unity among democrats.
2. the decline of the whig party.
3. a decline in the popularity of third parties.
4. the disappearance of the republican party.

The decline of the Whig party was an event in the 1850s.

Option 2.

Explanation:

From the time of 1830s to the time of starting of 1850s, the Whigs had joined the democrats and the two became the most powerful political party in the United States of America. In the year 1853, a Whig President, Millard Filmfore had occupied the White house also.

But two years later, in the year 1855, the Whig party completely declined and became extinct. The northern members of the Whig Party joined the anti slavery Republican party. The southern members of the Whig party joined the Navist American party and later the constitutional union party.

where is the rest of the question. this isn't making sense. can you upload a picture of the question?