Select the most more appropriate option to fill in the blank.
The passengers were afraid but the captain_________ them that there was no danger.

assured

The most appropriate option to fill in the blank is assured.

The word "assured" means to give someone confidence or to make them feel certain about something. In this context, it is the most accurate word to describe how the captain tried to calm the passengers' fears by telling them that there was no danger. The captain did not instruct, advise, or promise the passengers that there was no danger. He simply assured them.

The other options are not as appropriate.

• Instructed means to give someone directions or to tell them what to do. It is not the best word to describe how the captain tried to calm the passengers' fears because it does not capture the sense of reassurance.
• Advised means to give someone guidance or suggestions. It is not the best word to describe how the captain tried to calm the passengers' fears because it does not capture the sense of certainty.
• Promised means to make a commitment to do something. It is not the best word to describe how the captain tried to calm the passengers' fears because it does not capture the sense of reality.