Select the most 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 sentence is about the captain trying to calm the passengers' fears. The word "assured" is the most appropriate word to use because it accurately describes the action of giving someone confidence or certainty about something.

The other options are not as appropriate.

• Cautioned means to warn someone about something. It does not make sense in this context, because the captain is not warning the passengers about anything.
• Claimed means to state something as true, especially when it is not necessarily true. It does not make sense in this context, because the captain is not making a false statement to the passengers.
• Confided means to tell someone something secret. It does not make sense in this context, because the captain is not telling the passengers a secret.