When the Equation Si(s) + HF(aq) $\rightarrow$ SiF₄(g) + H₂(g) Is Balanced, What Is the Coefficient for Is

When the equation Si(s) + HF(aq) $\rightarrow$ SiF₄(g) + H₂(g) is balanced, what is the coefficient for HF?

A) 0
B) 1
C) 2
D) 3
E) 4