**The correct option is (C).**

Let x_{1},x_{2},x_{3},x_{4},...........x_{11} are distinct positive integers

Suppose the increasing order of the numbers are

⇒ x_{1},x_{2},x_{3},x_{4},x_{5},x_{6},x_{7},x_{8},x_{9},x_{10},x_{11}

**x**_{11} is largest number and the median is x_{6}.

Now, the median of first 10 numbers = (x_{5} + x_{6})/2

⇒ Let a = (x_{5} + x_{6})/2

Now, we have to replace largest number x_{11} by the median of first 10 numbers i.e. a.

So, new increasing order will be

⇒ x_{1}, x_{2}, x_{3}, x_{4}, x_{5}, a , x_{6}, x_{7}, x_{8}, x_{9}, x_{10}

And new median will be a i.e. (x_{5} + x_{6})/2

Which is lesser than the median of first eleven number x_{6}

**⇒ So, median decreases.**