For the reaction $aA+bB\rightarrow cC+dD$ the rate of formation of [C] in term of [A] is given by

Question

$\begin{array}{1 1}(a)\;\large\frac{d[C]}{dt}=\frac{c}{a}\frac{d[A]}{dt}&(b)\;\large\frac{d[C]}{dt}=-\frac{a}{c}\frac{d[A]}{dt}\\(c)\;\large\frac{d[C]}{dt}=-\frac{d[A]}{dt}&(d)\;\large\frac{d[C]}{dt}=-\frac{c}{a}\frac{d[A]}{dt}\end{array}$