The correct answers are: Assuming the caterer is arriving at noon, we will have plenty of time to set up the buffet. The mayor opens the new botanical garden tomorrow morning, and our reception follows immediately after. We are seating the in-laws at the back of the hall, whether they like it or not!

Explanation:

• Conditional Clauses: "Assuming" acts as a conditional conjunction (like if). We can use the present continuous (is arriving) inside a conditional clause to refer to a planned future event.

• Timetables: "Opens" and "follows" correctly use the present simple for scheduled, official public events.

• Personal Arrangements: "Are seating" correctly uses the present continuous for a fixed future arrangement.

Why the others are incorrect:

• "The moment" acts as a time conjunction. We must use a present tense (walks), not the future (will walk).

• You cannot use the present continuous (is melting) for a future prediction or result in the main clause of a conditional sentence. It must be "will melt" or "is going to melt."