Choose the correct answer. If you ... late, we ... at the conference now.

This is a mixed conditional: an unreal past condition (you were late — Past Perfect “hadn’t been”) with a present result shown by “now” (“could be”, would/could + bare infinitive). “could have been” refers to the past and clashes with “now”; «aren’t/will have been» and «haven’t been/will be» are real conditionals and do not fit an unreal situation.

Manba: UZBMB namunaviy test topshiriqlari (2022, mutaxassislik)