In a row of boys facing the north, A is $$16^{th}$$ from the left and C is $$16^{th}$$ from the right end. B who is $$4^{th}$$ to the right of A, is $$5^{th}$$ to the left of C in the row. How many boys are there in the row ?

A is 16th from the left, which means that there are 15 members to the left of A. C is 16th from the right, which means that there are 15 members to the right of C. It is also given that B is 4th to the right of A and 5th to the left of C. So, there are a total of 15 members to the left of A, 3 members between A and B, 4 members between B and C, and 15 members to the right of C in the row of boys. So, the total number of boys in the row is 15 + 3 + 4 + 15 + 3 = 40 boys. The last 3 in the calculation represent A, B and C.

Hence, the correct answer is option B.