Which of the following are Lenin's contribution of Marxist theory?
1. His theory of the party as 'the vanguard of the proletariat which guides the masses both before and after the revolution.'
2. His theory or capitalist imperialism, which he held to constitute the intermediary stage of capitalism.
3. His version for the reconstruction of the world's first proletarian state.
4. His theory of the strategy and tactics of revolution.
Select the correct answer:

A. 1 and 4

B. 1, 3 and 4

C. 1, 2 and 3

D. 1, 2, 3 and 4

Answer: Option B