She is travelling to Abuja. She'll return next week.

Analyze the question: You are given two short sentences and must pick the option that combines them while keeping the same meaning:

1. She is travelling to Abuja.
2. She'll return next week.

Concept: When two sentences give related information with no contrast between them, we join them with the coordinating conjunction "and". We use "but" only when the second idea contrasts with, or goes against, the first.

Step-by-step solution:

• Option A: "to return next week" makes returning the purpose of the trip. The original sentences don't say that, so the meaning changes. ✗
• Option B: "but" suggests a contrast, as if travelling and returning next week were opposing ideas. Nothing in the original sentences shows contrast. ✗
• Option C: "to returning" is ungrammatical, because "to" is followed by the bare verb ("to return"), not "returning". ✗
• Option D: "and" simply adds the second piece of information to the first. It is grammatically correct and keeps the original meaning: she is going to Abuja, and she will come back next week. ✓

Tip: In "combine the sentences" questions, ask yourself three things:

1. Does the new sentence keep the same meaning, without adding a purpose or a contrast?
2. Is the grammar correct (watch for errors like "to + -ing")?
3. Is the conjunction the right one? Use "and" for addition, "but" for contrast, and "so" for result.