Final answer:
The letter-starting greeting derived from Latin for health is 'Salutem', which is option D). It is a word associated with health and good wishes, different from 'Ave', 'Et tu', and 'Viva'.
Step-by-step explanation:
The correct answer to the question "This letter-starting greeting comes from the Latin for health" is D) Salutem. In Latin, 'salutem' pertains to health, safety, or well-being and is related to the greeting 'salve' which is used for both hello and goodbye, wishing someone good health.
Starting a letter with a word derived from 'salutem' is similar to sending good wishes or regards to the recipient. Option A) 'Ave' means 'hail' or 'welcome', B) 'Et tu' means 'And you' often associated with Caesar's last words, and C) 'Viva' is related to a form of the word 'live' or 'long live', but none of these relate as directly to health as option D).
This salutation is commonly used in Latin letters and translates to 'hello' or 'greetings'. It is similar to the English greeting 'Dear'.