Answer : The correct option is, (C) 19
Step-by-step explanation :
Median : It is the middle term that is sorted by the list of numbers. It is determine by placing the numbers in increasing order.
For odd observations the formula will be:

For even observations the formula will be:

As we are given that the set of data:
13, 15, 25, 17, 19, 20, 33
First we have to placing the numbers in increasing order.
13, 15, 17, 19, 20, 25, 33
Now we have to determine the median.
For odd data:

n = 7

The number at 4th position is, 19
Thus, the median of the given set of data of values is, 19