The correct option is B 2Au3+(aq)+6I−(aq)⟶2Au(s)+3I2(g)
The balanced reaction is as follows:
2Au3+(aq)+6I−(aq)⟶2Au(s)+3I2(g)
Au is getting reduced from +3 to 0.
Hence, there will be a factor of 3 before iodine in the product and hence, 6 before iodine ion.
I is getting reduced from −1 to 0.
According to the equation, there will be 2×1 electrons involved.
So, there will be a factor of 2 before Au and Au ion.
Hence, option B is correct.