Which best explains the meaning of "set our doubts at rest" as used in paragraph 9? communicate a suspicion

begin an investigation

search for clues

confirm a theory

“By an inspection of the trains, and by reckoning the time. The local police had to be called in, they had to communicate with Scotland Yard, Hopkins had to go out, and he in turn had to send for me. All that makes a fair night’s work. Well, here we are at Chiselhurst Station, and we shall soon set our doubts at rest.”

The institute of international research is holding its annual convention. this year more than 500 scholars have been invited to hear research reports on many timely topics. approximately 250 big name scientists will be winging their way to washington, d.c. how can the underlined sentence be revised so that it fits the tone of the passage? a) approximately 250 people will be in washington, d.c. b) approximately 250 bigwigs will be flying to washington, d.c. c) approximately 250 science people will be going to washington, d.c. d) approximately 250 well-known scientists will be arriving in washington, d.c.