Final answer:
To replace the first occurrence of a letter in a string with a question mark in Python, define a function 'replace_question(message)' using the provided code.
Step-by-step explanation:
To define a function called replace_question(message), which replaces the first occurrence of a letter (a-z and A-Z) with a question mark '?' in the string message, you can use the following Python code:
def replace_question(message):
for char in message:
if char.isalpha():
return message.replace(char, '?', 1)
return message
For example, 'Clemson University is the greatest university in the world!' would become '?????? ?niversity is the greatest university in the world!'