Solve the equation : $\;21x^{2}-28x+10=0\;$

Question

$(a)\;\large\frac{2}{27} \pm \large\frac{4}{27} i\qquad(b)\;\large\frac{5}{3} \pm \large\frac{\sqrt{2}}{21} i\qquad(c)\;\large\frac{2}{3} \pm \large\frac{\sqrt{14}}{21} i\qquad(d)\;\large\frac{\sqrt{2}}{27} \pm \large\frac{5}{27} i$