How Can It Be Said That Stalin's Cruelty Was Really

How can it be said that Stalin's cruelty was really a reaction to Leninist communism?

A) Stalin's reactions were often a response to a real chaotic situation that threatened the state.
B) Stalin was following the precise blueprint of Lenin's industrial plans.
C) Stalin was known to underplay situations until they got out of control.
D) There was never any serious threat to his leadership by the mid-1930s
E) Lenin had used massive purges to safeguard the revolution.