@Student1 Thank you for reaching out to Microsoft Q&A. I understand that you are having issues with disk selection not available for your student account.
It looks like there are capacity issues in few regions and there were few other customers who reported similar issues and below are few of them:
https://learn.microsoft.com/en-us/answers/questions/781150/azure-for-students-subsription-i-cannot-create-a-v.html
https://learn.microsoft.com/en-us/answers/questions/788334/no-size-selection-available-in-configuration-of-wi.html
https://learn.microsoft.com/en-us/answers/questions/789422/azure-vm-create-error.html
https://learn.microsoft.com/en-us/answers/questions/781744/vm-creation-issue.html
Please try to deploy the VM in West Europe as few customers acknowledged that this workaround helped in successfully deploying the VM.
Hope this helps.
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