2.
Pick the answer that completes the blank/s in the best, most suitable and accurate English.
'If they got out of London before the worst of the rush-hour, the earliest they ... ... 7:45 or so.'
... could of arrived here for supper would be ...
... would have arrived here for supper could be ...
... could arrive here for supper would be ...
... could arrive here for supper is ...
There is no need for 'that'/'when' or any form of subjunctive; English is perfectly clear without any such devices (unlike several other fine languages, possibly including yours!).