Please advise the correct answer for following Sentence:

The renowned Masai warriors of Kenya are among the world's tallest people, with an average height over six feet, several inches taller than in most other countries of the world.

A. taller than in
B. taller than that of
C. and taller than that of
D. which is taller than in
E. which is taller than it is in

OA is B

What is wrong with Option A.

It still compares the warrior of kenya to that in other countries against that of other countries. Is it the parallel structure.??

Thanks