Explanation:

- Economic boycott was intense and successful: The Non-Cooperation Movement included an economic boycott of goods, but its intensity and success varied across regions and over time.

- The middle class participated in very large numbers in the movement: The middle class's participation was initially enthusiastic, but it dwindled over time due to the economic strain and pressure from the colonial government. This is not entirely true for the entire course of the movement and is thus the correct answer.

- It was marked by uneven geographical spread and regional variations: The movement indeed experienced varying levels of engagement across different regions.

- Along with Non-Cooperation, other Gandhian social reform movements like the anti-liquor campaign achieved some success: This statement aligns with the dual objectives of the movement targeting both political and social reforms.