To arrange the substances from highest to lowest pH, we need to consider the chemical nature of each substance:
1. **Milk of Magnesia**: basic (high pH)
2. **Distilled Water**: neutral (pH around 7)
3. **Lemon Juice**: acidic (low pH)
Since basic substances have the highest pH, followed by neutral, and then acidic substances with the lowest pH, the correct order, from highest to lowest pH, is:
**Milk of Magnesia (highest pH), Distilled Water (neutral pH), Lemon Juice (lowest pH)**
Therefore, the correct answer is:
**D. milk of magnesia, distilled water, lemon juice**