The fe(ox33– complex ion creates an emerald green solution when dissolved. the observed solution color of the complex indicates the size of δ o is:

The choices can be found elsewhere and as follows:

A. in between. 
B. large. 
C. small. 
D. inconclusive, more information is needed. 

I think the correct answer is option C. The fe(ox33– complex ion creates an emerald green solution when dissolved. the observed solution color of the complex indicates the size of δ o is small.