On which aspect is the median score of the five vendors the least?

The correct option is Option 1 (Customer Service).

To find the aspect with the least median score, we first list the scores of all five vendors for each aspect and sort them in ascending order. The median is the middle value (the 3rd score in the sorted list of 5 scores):

1. Customer Service: 28, 41, 50, 55, 70
Median = 41

2. Reliability: 26, 40, 52, 60, 75
Median = 52

3. Reach: 46, 58, 63, 70, 80
Median = 63

4. Quality: 40, 48, 62, 69, 72
Median = 62

5. Features: 40, 45, 56, 75, 90
Median = 56

6. Cost: 50, 71, 77, 81, 90
Median = 77

Comparing all the medians, the minimum median score is 41, which corresponds to Customer Service.