Consider the Following Octahedral Complex Structures, Each Involving Ethylene Diamine

Multiple Choice

Consider the following octahedral complex structures, each involving ethylene diamine and two different, unidentate ligands X and Y. Which one of the following statements about these structures is incorrect?

A) Structures 1 and 2 are optical isomers.
B) Structures 1 and 3 are optical isomers.
C) Structures 1 and 3 are different complexes.
D) Structures 1 and 4 are geometrical isomers.
E) Structures 3 and 4 are the same complex.