Consider the following Python code:

def friendshipIsMagic$($twilight$)$:

if type$($twilight$)!=$ list:

return

else:

for pinkie in twilight:

if type$($pinkie$)!=$ str:

return

fluttershy $=$ open$("$rainbowdash$.$txt$","$w$")$

rarity $=[]$

for applejack in twilight:

for spike in applejack:

if spike not in rarity:

rarity.append$($spike$)$

fluttershy.write$($str$($rarity$))$

fluttershy.close$()$

What does the code primarily do$?$

A$.$ Creates a new text file named "rainbowdash.txt$"$ and writes to it strings

from the list twilight.

B$.$ Writes unique characters found in each string in the list twilight to the existing content of "rainbowdash.txt$".$

C$.$ Prints the lists of unique characters found in the file "rainbowdash.txt$"$

D$.$ Creates a new text file named "rainbowdash.txt$"$ and writes to it a list containing the unique characters found in the list twilight.