The word "dubious" ( Line 2, Para. 2 ) most probably means ______.

A．eighty percent of American working people were employed in factories
B．twenty percent of American intellectuals were employees
C．the percentage of intellectuals in the total ~work force was almost the same as that of industrial workers
D．the percentage of intellectuals working as employees was not so large as that of industrial workers

It was the day before yesterday ______ the witness saw the murderer drinking in a public house on the Fifth Avenue.A ) the time B) when C ) that D ) which