Question about shrink the log file in the SQL Server database

Hi Guys,

The log file in my development server is going to be full soon as presented below:

I did already a backup of the log file using the command:

BACKUP LOG DEV TO DISK='D:\BACKUP\DEVLOG1.BAK'

My question is, In the screen below which option is the better one to select?

I already shrinked the file to 10MB but is not releasing much space.

Could I select the first option named "Release unused space" to release more space in this log disk or what I could do?

Thanks for the help!