Đó means like far but not that far.
Kia means very far
If wrong blame my vietnamese teacher
"That is her " is idiomatic but grammatically inconsistent with the rule that the verb "to be " takes a predicate nominative. "That is she" is correct, grammatical and actually used in speech. "That is her " has been called a "sturdy indefensible " because it is so resistant to correction in colloquial speech.
Why the minus 2? I answered as I was taught in school. "It is she" is and always has been correct. Some people even say ít in conversation. I usually do not but in an exercise I tried to be proper, only to be told that the grammatical answer was incorrect. DL should not be rejecting perfectly good English.
As i figured it out..kia has to be used for things or persons close to the speaker ( not emotionally i think
As a native speaker of (Middle Atlantic) American English I would say, "That is she" as often as "That is her."