Which of the following collections are sets?
(i) The collection of all the oceans in the world
(ii) The collection of all poor people in the world
(iii) The collection of all multiples of 8
(iv) The collection of all letters of word APPLE .

Explanation

To determine which of the given collections are sets, we need to check if each collection is well-defined. A collection is considered a set if it has a clear definition and does not vary from person to person. Let's analyze each option step by step.

### Step 1: Analyze the collection of all the oceans in the world
- **Definition**: The oceans are a fixed number and universally recognized.
- **Conclusion**: This collection is well-defined and does not vary from person to person. Therefore, it is a set.

### Step 2: Analyze the collection of all poor people in the world
- **Definition**: The definition of "poor" can vary significantly depending on individual perspectives and criteria.
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