To determine if the relationship between the time walking and calories burned is proportional, we can check if the ratio of calories burned to time walking is constant for all the entries in the table.
Let's calculate the ratios for each time and corresponding calories burned:
- For 20 minutes: \( \frac{100 \text{ calories}}{20 \text{ minutes}} = 5 \)
- For 30 minutes: \( \frac{150 \text{ calories}}{30 \text{ minutes}} = 5 \)
- For 40 minutes: \( \frac{200 \text{ calories}}{40 \text{ minutes}} = 5 \)
- For 60 minutes: \( \frac{300 \text{ calories}}{60 \text{ minutes}} = 5 \)
- For 80 minutes: \( \frac{400 \text{ calories}}{80 \text{ minutes}} = 5 \)
Since all the ratios are equal (all equal to 5), the relationship is proportional.
Thus, the correct answer is:
A. The relationship is proportional.