Let the function f be defined by f(x)=\(\frac{9+3x}{7-2x}\), then f-1(x) is ______

• A. \(\frac{9-3x}{7+2x}\)
• B. \(\frac{7x-9}{2x+3}\)
• C. \(\frac{2x-7}{3x+9}\)
• D. \(\frac{2x-3}{7x+9}\)