Chọn câu đúng? 1/(x + 2) - 1/(x + 2)(4x + 7) = 4x/(x + 2)(4x + 7)

A. $\frac{\text{1}}{\text{x}+\text{2}}-\frac{\text{1}}{\text{(x}+\text{2)(4x}+\text{7)}}=\frac{\text{4x}}{\text{(x}+\text{2)(4x}+\text{7)}}$

B. $\frac{\text{2}-\text{21x}}{\text{18}}-\frac{\text{4}+\text{x}}{\text{12}}=\frac{\text{75x}-\text{16}}{\text{36}}$

C. $\frac{\text{1}}{\text{x}+\text{4}}-\frac{\text{1}}{\text{x}+\text{5}}=\frac{\text{1}}{\text{(x}+\text{4)(x}+\text{5)}}$

D. $\frac{\text{2}}{\text{x}-\text{5}}+\frac{\text{3x}}{{\text{x}}^{\text{2}}-\text{25}}=\frac{\text{4x}+\text{5}}{{\text{x}}^{\text{2}}-\text{25}}$