Which one is correct

[مستر رمضان عيسى]

ON PAGE 316 TG the book answered this sentence
I got up late and missed the bus . [If
If I get up late, I'll miss the bus
If I hadn't got up late, I wouldn't have missed the bus

Which one is correct
the author answered

Both are acceptable answers. While most teachers would
expect the second answer — the third conditional, talking about an unreal event in the past — the first answer could be spoken by someone who has learned from a past mistake: If I get up late (again), I'll miss the bus.

We want students to see that, in many cases, their meaning decides the grammar. The words, phrases, and verb forms they choose depend on the meaning they want to express, or the context (level of formality, written or spoken language) in which they are communicating.