Help the dog owner figure out what her pet is feeling by choosing the correct word.

Look at Buster drooling over that fallen slice of pepperoni pizza. He hasn't eaten all day, so he ___ be absolutely starving!

The correct answer is must.

When we are almost 100% sure that something is true based on present evidence (like drooling and not eating all day), we use the modal verb must for deduction.

"Might" is only used when we are unsure, and "can't" is used when we are sure something is impossible.