The erroneous part is 3. Key Points 'you must be hungry' should be there in place of 'you can be hungry' Modals are used as helping verbs in sentences to express certainty, possibility, willingness, obligation, necessity or ability. The modal 'must' denotes moral obligation or strong possibility. Example​ There is somebody at the door. That must be the postman. (= I think that is certainly the postman.) We know that 'can' expresses the ability to do something. If one is able to do something today, he must not put it off till tomorrow. Example: Aastha can do this work. We use 'can' to talk about things that we think are usually, but not always, true. Example: Reducing cholesterol through diet can be difficult. (It’s not always difficult for everyone, but in general, it is difficult.) ​Here in the given sentence, a strong possibility is being talked about. So it preferable to use 'must' The correct sentence is: You haven’t eaten all day, you must be hungry and tired.