Once the following equation is balanced with the smallest set of whole number coefficients, what is the sum of the coefficients? (Don't forget to include coefficients of one.)

__ SF_{4} + __ H_{2}O → __ H_{2}SO_{3} + __ HF

▸ 4

▸ 6

▸ 7

▸ 9

▸ None of these answers is correct.