Final answer:
John is an expatriate because he is a British citizen working in Germany; he is living outside his home country for employment purposes with Ford.
Step-by-step explanation:
John, a British citizen working for Ford in Germany, is a expatriate. An expatriate is someone who is living and working in a country other than their country of citizenship, often temporarily and for work reasons. In John's case, his home country is the UK, but he is in Germany for work purposes. The other terms are defined as follows: a third-country national is an individual who is working in a country where neither they have citizenship nor is it the country of the headquarters of the company they work for; a host-country national is a person who is working in their own country for a foreign company; and home-country national refers to individuals working in their own country for a company headquartered in their same country. Therefore, for John, answer choice b. expatriate, correctly describes his situation.