In a queue of 23 persons waiting at a bank counter, there are 9 persons between Rajeev and Heena. Prachi is exactly in the middle of Rajeev and Heena. Tushar is $$3^{rd}$$ from the front and there are five persons between Heena and Tushar. What is Prachi's position from the back?

We are given that there are 9 people between Rajeev and Heena. 
R _ _ _ _ _ _ _ _ _ H

Next, we are given that Prachi is exactly between Rajeev and Heena. 
R _ _ _ _ P _ _ _ _ H

We are given that Tushar is 3rd from the start 
T 2 1

We are given that there are five people between Rushar and Heena. 
Now, Tushar cannot be to the left of Heena because that would mean that the arrangement:
R _ _ _ T P _ _ _ _ H

In which case, he cannot be the third from the start
Therefore, he must be standing to the right of Heena

R _ _ _ _ P _ _ _ _ H _ _ _ _ _ T _ _

Making Heena's position from the start to 9th and Prachi's position to be 14th

Since there are 23 people in the line, Prachi's position from the back would be 23-14+1 = 10th

Therefore, Option C is the correct answer.