Final answer:
Harriet Tubman became famous for assisting slaves to escape to Canada via the Underground Railroad. The correct answer is option a.
Step-by-step explanation:
Harriet Tubman gained fame by helping slaves to escape to Canada. Born a slave in Maryland around 1822, Tubman escaped from slavery in 1849 and became a revered figure in the abolitionist movement. She returned to the South at least thirteen times to assist around seventy family members and friends to freedom through the Underground Railroad. Her efforts were in defiance of the Fugitive Slave Law of 1850, and instead of advocating for it, she became an icon of resistance and liberty, taking great risks to guide others to safety in the North and Canada, where slavery was abolished.