Final answer:
The addition of vitamins A and D to milk is called fortification, which is different from pasteurization or homogenization and serves to enhance the milk's nutritional value. Hence, option (d) is correct.
Step-by-step explanation:
The process of adding vitamins A and D to milk is known as fortification. This is a practice wherein nutrients are added to foods to enhance their nutritional value. Fortification can be done to replace vitamins and minerals lost in processing, a process known as enrichment, or to add nutrients that may be lacking in the diet.
Examples of other processes that are sometimes confused with fortification include pasteurization, which is the heating of milk to destroy harmful bacteria, and homogenization, which is the process of breaking down fat molecules in milk so they remain integrated rather than separating.
In contrast to fortification, UHT pasteurization is a method of pasteurization that exposes milk to ultra-high temperatures for a brief period, sterilizing it so that it can be stored for long periods without refrigeration. However, this process does not involve the addition of nutrients.
To answer the question, the correct option for the process of adding vitamins A and D to milk is fortification (option d). This helps ensure that consumers receive essential nutrients, which may especially be beneficial for those adapting to dairy foods and in need of key vitamins like vitamin D.