Final answer:
The new median of the data after increasing each observation by 5 is 26.
Step-by-step explanation:
To find the new median after increasing each observation by 5, we need to first determine the new position of the median in the data set. Since the median is the value that divides the data into two equal halves, if we increase each observation by 5, the median will also increase by 5. Therefore, the new median will be 26, which is option a.