Get title of referenced item two levels deep with Search API
None of the relations information is stored in C, so when you have C views it can't show relations info out-of-box. 

Usually the way to show the "Child" for a "Parent" node is by using the Contextual filter for the Entity Reference field with the "provide default value" and "Content ID from URL" options. In your case A is a child of B, and B is a child of C. 

Then you can use the Custom text field to construct your text, you can use the Contextual arguments in that field, this will give you information about the "Child" of the node in view row. 

Maybe you can work through that to get to the "Grandchild" info, I haven't tried it. 

I'd suggest chaining the reverse Relationships, they are called something like "Content referenced from field_my_reference", first you add the one for the child, then add another Relationship for the grandchild, and make the second Relationship use the First one. That's how you get to correct nodes. 

Add the fields for the B and A titles with using the correct Relationship for each. Thena again you can use the Custom text field to override how their output is worded. You can "Exclude from display" the fields you use in Custom text after you have it showing the way you want inside Custom text.