Meaning 3x100 MB? By default, yes. It is possible to install ML-package-1.2 into your 'base' python and then have virtual environments A,B and C all use that

Meaning 3x100 MB? By default, yes. It is possible to install ML-package-1.2 into your 'base' python and then have virtual environments A,B and C all use that instead of installing their own copies. However this is generally not considered best practice.