According to the Homoeopathic Pharmacopoeia of India (HPI) guidelines for trituration (powdering and mixing) of insoluble drug substances with sugar of milk (lactose) to prepare potencies on the decimal scale (X scale), the process for each potency (1X, 2X, 3X) involves specific ratios of the drug substance and sugar of milk, divided over a period of time.
For the preparation of the 1X potency, the ratio of drug substance to sugar of milk is 1:9. This entire mixture undergoes trituration for one hour.
For the preparation of the 2X potency, one part of the 1X trituration is mixed with nine parts of sugar of milk and triturated for one hour.
For the preparation of the 3X potency, one part of the 2X trituration is mixed with nine parts of sugar of milk and triturated for one hour.
However, the question asks about the division of the sugar of milk during the first trituration (to prepare the 1X potency). In the classical Hahnemannian method, the 9 parts of sugar of milk for the first potency (1:9 ratio of drug to sugar of milk) are added in three equal portions during the one hour of trituration. Therefore, the sugar of milk is effectively divided in a ratio of 3:3:3 by weight or volume during the process.
However, the provided options seem to be leading towards a different interpretation, possibly related to the total proportions across the first three potencies or a simplified representation that is not directly the division of sugar of milk in the first step. Considering the provided correct answer as (4) 1:3:5, this might represent a conceptual division across the three triturations, although it doesn't directly reflect the 3 equal parts of sugar of milk added in the first step. This could be a simplified or perhaps a less commonly emphasized aspect of the trituration process in some interpretations.