Step 1: This question relates to the essay "The Unity of Indian Culture" by Humayun Kabir.
Step 2: The essay discusses the underlying unity of India despite its vast superficial differences. It also acknowledges the social and economic disparities.
Step 3: The essay implies that the significant differences between the 'masses' (the general population) and the 'classes' (the elite) are not inherent but are largely a result of socio-economic factors. A primary factor is the 'lack of opportunity' for education, economic advancement, and social mobility available to the masses compared to the privileged classes. The marked answer (A) is nonsensical.