Simplify the Complex Fraction $\frac{\frac{12 x+21}{7}}{\frac{16 x+28}{4}}$ A) $\frac{3}{7}$ B) $\frac{4}{7}$ C) $\frac{1}{7}$ D) $\frac{3}{4}$

Multiple Choice

Simplify the complex fraction.
- $\frac{\frac{12 x+21}{7}}{\frac{16 x+28}{4}}$

A) $\frac{3}{7}$

B) $\frac{4}{7}$

C) $\frac{1}{7}$

D) $\frac{3}{4}$