Answer:
A. Louisa's car is old.
Step-by-step explanation:
A metaphor is a comparison between unlike things without using like or as. In this sentence the metaphor is "Louisa's car was a dinosaur". Louisa's car is being compared to a dinosaur. The purpose of the metaphor is to show that Louisa's car was old. Dinosaurs were alive thousands of years ago and are now extinct. This comparison is not saying that Louisa's car is a thousand years old, but rather that it's so old, it should probably be extinct.