The correct answer is A) Landless laborers.
The growth of the plantation economy in Kerala led to the rise of a class of landless laborers. These laborers were often poor and uneducated, and they worked long hours in difficult conditions for low wages. They were often exploited by their employers, and they had little opportunity to improve their lives.
The growth of the plantation economy also led to the decline of the traditional agricultural economy. Many farmers were forced to sell their land and move to the cities in search of work. This led to an increase in urban poverty and unemployment.
The plantation economy also had a negative impact on the environment. The clearing of forests to make way for plantations led to soil erosion and deforestation. The use of pesticides and herbicides polluted the water and soil.
The plantation economy has had a significant impact on the social, economic, and environmental development of Kerala. It has led to the rise of a class of landless laborers, the decline of the traditional agricultural economy, and the degradation of the environment.
Option B, industrial workers, is incorrect because the plantation economy is not an industrial economy. Option C, Zamindar landlords, is incorrect because the plantation economy is not a feudal economy. Option D, merchant guilds, is incorrect because the plantation economy is not a commercial economy.