If the median of an increasing sequence 1,20,35,c, d,78,100,1501,20,35,c, d,78,100,150 is 48. what is the sequence?

In statistics, the median is the centermost number in a given set that separates them from the highest set and the lower set. To get the median, you must arrange first the data set in increasing order. It would be easy if the number of data is odd but if it is even, it is different. So you must find the two middle pairs, add them and divide it by two. 
 

The correct answer is: b