নিচের কোন বিক্রিয়াটিকে \( \mathrm{Fe}^{3+} \) আয়নের সুনিশ্চিতকরণ পরীক্ষা হিসাবে ধরা হয়?

A \( 4 \mathrm{Fe}^{3+}(\mathrm{aq})+3 \mathrm{~K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right](\mathrm{aq})= \) \( \mathrm{Fe}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]_{3}+12 \mathrm{~K}^{+}(\mathrm{aq}) \)

B \( \mathrm{Fe}^{3+}(\mathrm{aq})+3 \mathrm{NH}_{4} \mathrm{CNS}(\mathrm{aq})=\mathrm{Fe}(\mathrm{CNS})_{3}(\mathrm{aq})+ \) \( 3 \mathrm{NH}_{4}^{+}(\mathrm{aq}) \)

C \( \mathrm{Fe}^{3+}(\mathrm{aq})+3 \mathrm{NH}_{4} \mathrm{CNS}(\mathrm{aq})=\mathrm{Fe}(\mathrm{OH})_{3}(\mathrm{aq})+ \) \( 3 \mathrm {NH}_{4}^{+}(\mathrm{aq}) \)

D \( \mathrm{Fe}^{3+}(\mathrm{aq})+3 \mathrm{~K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{2}\right](\mathrm{aq})= \) \( \mathrm{Fe}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{2}\right]_{3}+6 \mathrm{~K}^{+}(\mathrm{aq}) \)

E \( 2 \mathrm{Fe}^{3+}(\mathrm{aq})+3 \mathrm{~K}_{2}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right] \mathrm{aq}= \) \( \mathrm{Fe}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]_{3}+6 \mathrm{~K}^{+}(\mathrm{aq}) \)