(A) 2
(B) ** 1
(C) 3
(D) 4
EXPLANATIONS BELOW
Concept note-1: -Barack Hussein Obama II (/bəˈrɑːk huːˈseɪn oʊˈbɑːmə/ ( listen) bə-RAHK hoo-SAYN oh-BAH-mə; born August 4, 1961) is an American retired politician who served as the 44th president of the United States from 2009 to 2017.
Concept note-2: -The Democratic ticket of Barack Obama, the junior senator from Illinois, and Joe Biden, the senior senator from Delaware, defeated the Republican ticket of John McCain, the senior senator from Arizona, and Sarah Palin, the governor of Alaska.
Concept note-3: -The first piece of legislation signed by Obama was the Lilly Ledbetter Fair Pay Act on January 29, which promoted fair pay regardless of gender, race, or age. Lilly Ledbetter joined Obama and his wife, Michelle, as he signed the bill, fulfilling his campaign pledge to nullify Ledbetter v. Goodyear.