The correct option is A 14th
Since Kashish and Mona interchange places, so Kashish's new position (13th from left) is the same as Mona's earlier position (6th from right).
So, number of children inn the queue=(12+1+5)=18.
Now, Mona's new position is the same as Kashish's earlier position i.e., fifth from left.
∴ Mona's position from the right = (18 - 4) = 14th