Choice Dhoice D is the correct answer. Division by 25 gives us the solution.

1. Start with the equation: $25x = 100$
2. Divide both sides by 25: $x = \frac{100}{25}$
3. Simplify: $x = 4$
4. Verify: $25(4) = 100$ ✓

💡 Mental Math: Recognize that $25 \times 4 = 100$ (four quarters make a dollar!), so $\frac{100}{25} = 4$.

Choice Dhoice C is incorrect because this results from subtracting: $100 - 25 = 75$. Subtraction is not the inverse of multiplication.

Choice Dhoice A is incorrect because this comes from adding: $100 + 25 = 125$. Addition doesn't undo multiplication.

Choice Dhoice B is incorrect because this results from multiplying: $100 \times 25 = 2500$. This makes the product larger instead of isolating $x$.