Theoretically, the caste system can be understood as the combination of two sets of principles. Each caste is supposed to be different from – and is therefore strictly separated from – every other caste. Many of the scriptural rules of caste are thus designed to prevent the mixing of castes – rules ranging from marriage, food sharing and social interaction to occupation. On the other hand, these different and separated castes do not have an individual existence – they can only exist in relation to a larger whole, the totality of society consisting of all castes. Further, this societal whole or system is a hierarchical rather than egalitarian system. Each individual caste occupies not just a distinct place, but also an ordered rank – a particular position in a ladder-like arrangement going from highest to lowest.

The hierarchical ordering of castes is based on the distinction between

Purity and pollution.

The correct answer is Option 1: Purity and pollution.

Option 1: Purity and pollution. Correct. The hierarchical ordering of castes is based on the distinction between ritual purity and pollution. This principle determines the relative ritual status of different castes within the caste hierarchy.

Option 2: Ritual status and occupational specialisation. Incorrect. Occupational specialisation is a feature of the caste system because each caste is traditionally associated with a particular occupation. However, occupational specialisation is not the principle on which the hierarchy is based. The hierarchy is determined by the distinction between purity and pollution, while occupation is linked to the functioning of the caste system as a social division of labour.

Option 3: Economic power and political authority. Incorrect. Economic and political power may influence a caste's social standing, and historians believe that historical processes such as conquest also affected caste status. However, these factors do not constitute the basic principle governing the hierarchical ordering of castes.

Option 4: Birth and educational attainment. Incorrect. Caste membership is determined by birth, but educational attainment is not the basis of the traditional caste hierarchy. The hierarchy is founded on the ritual distinction between purity and pollution rather than educational achievement.