Final answer:
Option (B), Abraham Lincoln faced the crisis of the secession of Southern states as he became President, leading to the Civil War between the North and the South.
Step-by-step explanation:
When Abraham Lincoln assumed the role of President of the United States, he was faced with the crisis of B. Secession of Southern states. The tensions between the North and the South, primarily over the issue of slavery, had reached a critical point. After the Republican Abraham Lincoln won the 1860 presidential election, Southern states feared the impact on their way of life and began to secede.
The seven states of the Lower South seceded before Lincoln's inauguration, leading to a civil war between the Confederate South and the Union North from April 1861 to April 1865. This crisis of secession was the immediate challenge Lincoln faced upon entering office.