Answer: ``` gcloud compute instances create instance1 gcloud config set compute/zone europe-west2-b gcloud compute instances create instance2 ```, ``` gcloud compute instances create instance1 gcloud compute instances create instance2 --zone=europe-west2-b ```

The correct approach involves either changing the default compute/zone property to `europe-west2-b` before creating the second instance or specifying the zone directly in the create command for the second instance. The first option (`A`) would create both instances in `europe-west2-a` because it doesn't change the default zone or specify a different zone for the second instance. Option `D` and `E` attempt to change the default zone but use incorrect syntax (`zone` instead of `compute/zone` in `D` and `configuration set` instead of `config set` in `E`). Options `B` and `C` correctly address the requirement by either updating the default zone to `europe-west2-b` before creating the second instance (`B`) or specifying `europe-west2-b` as the zone for the second instance directly in the create command (`C`).

Author: LeetQuiz Editorial Team