Take a look at the item again:
With her heavy dictionary, (A)
Donna thumps the top of her ancient computer
monitor. (B)
Whenever the color tint flickers
(C) from normal to sickly yellow.
You wanted to to this:
With her heavy dictionary, Donna thumps the top of her ancient computer
monitor. Whenever the color tint flickers. From
normal to sickly yellow.
Adding a period after flickers will make from normal to sickly yellow a fragment.
You might want to review the rules.
Go back to the sentence to try again.