Answer:
Hi!
The answer to your question would be option B. To show that the sister’s lie is harmless
Step-by-step explanation:
To find the answer we should first know what a "fib" is. Fib is defined as a lie, typically an unimportant one.
Now that we know that the sister is telling an unimportant lie, we can check with the options and see that option B, to show that the sister’s lie is harmless, is the one that perfectly matches.