Answer
chr(randint(ord("B"), ord("M")))
Work Step by Step
The function ord will provide the ASCII code of B and M, and the randint function will give a random integer between the ASCII value of B and M, inclusive of both. And char will convert the final ASCII value to the corresponding character.
This solution uses the fact that ASCII code contains the alphabets in contiguous order so the character between B and M will also have their ASCII code between the ASCII code of B and M.
randint is a function imported from random library of python.
