Does Azure AD B2C sign in policy support configuring case sensitive when using email sign in?

We are using Azure AD B2C to do identity management, and allow user to use email to sign in.

Currently it seems that the email field is not case sensitive when signing in. For example, the email is admin@contoso.com. I can use it to sign in. And I also can sign in with ADmin@contoso.com.

My question is

1. Whether does Azure AD B2C have configuration to enable/disable case sensitive for the field email? (If disable, it means that I can only sign in with admin@contoso.com)
2. If can not be configured to disable case sensitive, which culture settings does it use for the case insensitive comparisons?

Thanks.