1. I’m really excited about my trip next week. I'm looking forward to going …
a. Australia. - Wrong - there should be another preposition in this sentence
b. to the Australia. - Wrong – 'the' isn’t usually used before country names (there are a
few exceptions e.g. the United States, the Maldives, the United Kingdom)
b. to Australia. – Correct – we rarely use articles before country names
d. to an Australia. – Wrong – 'an' or 'a' is never used before country names