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.”

Answer is in the file below

cutt.ly/tz3yDpb

the choice that is not a technique that you should use to come up with ideas for the topic of a research project is, writing about academic subjects that are not interesting to you. this does not belong to the techniques to come up with ideas because having no interest in a certain topic will lose your drive to come up with better ideas. it gives no room for improvement and acquiring of new ideas and information. 

explanation:

alright no problem, cool