Choose the correct letter, A, B or C. The building constructed by the first Europeans at the observatory was

Could I have your attention please... gather round, gather round. My name is Charlie and I’ll be your guide around the Sydney Observatory. Now, as you all will know, man has been interested in the night sky for a very long time. Indeed, before the invention of the compass, it was used by sailors to navigate their way across the world’s oceans. A kind of a ’star’ map, you could say.
Now, the site of the museum on Observatory Hill has its own interesting story. Before the colonisers arrived, it belonged to the Gadigal people, who may have even viewed the arrival of the new visitors from here, as this is the highest natural point in Sydney Harbour. The early Europeans then built a windmill on the site though it didn’t last for long due to its exposed position. A little while after that, the land was used to build a fort, which was to finally become the observatory that you see before you today.
Now, let’s take a look inside. To the left of the main entrance is the cloakroom where you can leave your coats and bags, but please make sure you don’t leave any mobiles or valuables, as staff cannot be held responsible. The museum is open during the day until 5 p.m., so please collect belongings no later than 5:15 and please vacate the building by 5:30. No new admissions will be allowed after 4:30 p.m. After you’ve left your personal items, you’ll need to buy your tickets from the ticket desk immediately behind you before continuing on the rest of the tour. The normal price is $8 for an adult and $6 for a child, though groups of up to four people can save money by buying a family ticket. This must contain at least one adult and one child but no more than two children per adult I’ll wait for you on the other side of the ticket area by the coffee shop while you all get your tickets.
So, I hope you enjoyed the tour, but, before I leave you I just want to draw your attention to one more thing. Your observatory ticket also entitles you to visit another of Sydney’s famous sights at a 50% discount. You’ll find lots on to keep the children entertained. For example, they’ve got a sound workshop where you can have a go at being a DJ. This is called the Sound House, and you’ll find it up on the second floor, just after the kid’s playground. Look for signs for the Vectorlab Workshops if you get lost. For those of you interested in fashion and design, the Lace Study Centre should not be missed. You’ll get the chance to look at one of the country’s best collections all in one place. However, like most museums, only a fraction of their collections are actually on display, but in the museum’s Discovery Centre, you can take the opportunity to go behind the scenes and see parts of the collection that are not on display. All of these attractions can be found under one roof at Sydney’s famous Powerhouse Museum. I do hope you are able to go and enjoy the experience. You won’t be disappointed!