In my org file, I have ordered capital lettered plain lists like this:

A. Item A
B. Item B
    a. subitem a
    b. submitem b
C. Item C


But when I export them to a pdf via latex, they look like this:

1. Item A
2. Item B
    (a) subitem a
    (b) submitem b
3. Item C


Is this a bug or is it expected behavior?

--- test .org file ----------------

A. Item A
B. Item B
   a. subitem a
   b. submitem b
C. Item C

-- my setup --------------------
Emacs  : GNU Emacs 25.1.1 (i686-w64-mingw32)
 of 2016-09-17
Package: Org mode version 9.0.1 (9.0.1-elpa @
c:/Users/scott/OneDrive/scotto/.emacs.d/elpa/org-20161118/)