Read the passage from "Stalin: A Brutal Legacy Uncovered,” which is an informational text about Stalin’s atrocities and how he used ambition and fear to rule over people of the Soviet Union. As Khrushchev informed the closed session of the Party apparatchiks, his report—which has entered history as the "Secret Speech"—was based on research by a special commission of senior leaders of the Communist Party. It covered primarily only one part of Stalin's murderous record: (underlined portion: the peak years of his savage "Great Purge" in the mid- and late 1930s, a massacre that wiped out a whole generation of Bolsheviks, the Party's oldest and most faithful members.)

Khrushchev, who went on to become the Soviet prime minister, said next to nothing about the rest of Stalin's victims, who have been estimated at more than 20 million.

Stalin's genocidal record was the product of a ruthless, steely personality hardened by searing hardships in his youth: first, brutal beatings by his alcoholic, dirt-poor father; and later, several rounds of imprisonment and exile—from which he often escaped—following his expulsion from a Russian Orthodox seminary for fomenting a strike of railroad workers. For the 20-year-old Stalin, an outstanding student with top marks in Bible and Church studies, the strike was the first step on a new road - a career of rebellion, crime, and radical politics that eventually made him the unquestioned boss of the Communist Party and of 140 million people in the Soviet Union.

Which phrase best explains the purpose of the underlined text?

to give evidence of Stalin’s genocidal actions
to explain why Stalin became a ruthless murderer
to focus the reader’s thoughts on Stalin’s personality
to summarize Stalin’s time as a Communist leader