Geometrical Isomerism in Octahedral Geometry

Q. Which one of the following has the largest number of isomers?

1. $\left[Co\right(en{)}_{2}C{l}_2{]}^{+}$
2. $\left[Co\right(N{H}_3{)}_{5}Br{]}^{2+}$
3. $\left[Ir\right(PP{h}_3\left)\right]\left(OH\right)\left(CO\right){]}^{2+}$
4. $\left[Ru\right(N{H}_3{)}_{5}Cl{]}^{2+}$

Q. Read the following questions and answer as per the directions given below:

Statement I: The geometrical isomers of the complex $\left[M\right(N{H}_3{)}_{4}C{l}_2]$ are optically inactive.
Statement II: Both geometical isomers of the complex $\left[M\right(N{H}_3{)}_{4}C{l}_2]$ possess axis of symmetry.
(IIT-JEE, 2008)

1. Statement I is true; Statement II is also true; Statement II is a correct explanation for Statement-I.
2. Statement I is true; Statement II is true; Statement II is not the correct explanation for Statement-I.
3. Statement I is true; Statement II is false.
4. Statement I is true; Statement II is true.

Q.

Number of possible isomers for the complex $\left[Co\right(en{)}_{2}C{l}_2]Cl$ will be (en = ethylenediamine)

1. 2

2. 1

3. 3

4. 4