Identify and differentiate categories of fruits in a legal context, specifically distinguishing natural fruits from civil fruits.

The question asks to identify categories of natural fruits. In legal and property contexts, fruits are often classified based on their origin and status.

• (i) Hanging fruits: These are natural fruits that are still attached to the plant or tree. They are considered part of the land until they are harvested.
• (ii) Civil fruits: These are revenues or income generated from a thing, such as rent from a property, interest from money, or dividends from shares. They are not natural products of the earth or animals.
• (iii) Separated fruits: These are natural fruits that have been detached or harvested from the plant. Once separated, they become movable property.
• (iv) Gathered fruit: This term is synonymous with separated fruits, referring to natural fruits that have been collected or harvested.

Therefore, "Hanging fruits," "Separated fruits," and "Gathered fruit" are all categories of natural fruits. "Civil fruits" are a distinct legal category of income, not natural products.

Based on this, the correct categories are (i), (iii), and (iv).

Comparing this with the given options:
a. (i), (ii), (iii) and (iv). (Incorrect, includes civil fruits)
b. (i), (ii) and (iii). (Incorrect, includes civil fruits)
c. (ii) and (iii). (Incorrect, includes civil fruits and misses hanging/gathered fruits)
d. (i), (iii) and (iv). (Correct)

The final answer is $\boxed{\text{d}}$