$\dfrac{\dfrac{1}{a^2}+\dfrac{1}{b^2}+\dfrac{2}{ab}-\dfrac{c^2}{a^2b^2}}{\left(\dfrac{c}{ab}-\dfrac{1}{a}-\dfrac{1}{b}\right)(a+b+c)}$ ifodaning qiymatini $a=2{,}4;\ b=\dfrac{5}{6}$ va $c\ne\pm(a+b)$ bo‘lganda hisoblang.
- A. $-\dfrac{1}{2}$
- B. $-2$
- C. $\dfrac{1}{2}$
- D. $-\dfrac{1}{4}$