Why Has Evangelical Christianity Gained Adherents in Russia and the Post-Soviet

Why has evangelical Christianity gained adherents in Russia and the post-Soviet states in recent decades?

A) as a result of the official persecution of traditional state religions
B) as a result of government efforts to hide social problems by requiring residents to attend religious ceremonies
C) because of the region's close ties to centers of world religion such as the Vatican and Tibet
D) because the evangelical belief that economic success comes from faith is very appealing to the struggling people of the region