Answer: ```python def add_integers(x, y): return x + y ```

## Explanation Let's analyze each option: **Option A**: Incorrect. Python uses `def` keyword to define functions, not `function`. The syntax is wrong. **Option B**: Incorrect. Same issue as Option A - uses `function` keyword instead of `def`. Also, the function doesn't return anything explicitly. **Option C**: Incorrect. While it uses the correct `def` keyword, it prints the result instead of returning it. The requirement is to "return the sum", not print it. **Option D**: **CORRECT**. This uses the proper Python syntax with `def` keyword, takes two parameters `x` and `y`, and returns their sum using the `return` statement. **Option E**: Incorrect. Uses correct `def` keyword but doesn't return the result. In Python, if you don't explicitly return a value, the function returns `None`. **Key Python concepts**: 1. Functions in Python are defined using the `def` keyword 2. The `return` statement is used to return a value from a function 3. Without a `return` statement, a function returns `None` by default 4. `print()` outputs to console but doesn't return a value for further use in code

Author: Keng Suppaseth