Slave who sued for his freedom in what became a famous supreme court act

Dred Scott (c. 1799 – September 17, 1858) was an enslaved African American man in the United States who unsuccessfully sued for his freedom and that of his wife and their two daughters in the Dred Scott v. Sandford case of 1857, popularly known as the "Dred Scott case".

offline recommendation systems option b

because recommendation systems produce a list of two ways

1. through collaborative filtering

or

2. through content-based filtering