Correct Answer & Explanation
Option A
• In imperative sentences, the reporting verb 'said to' is changed into verbs like 'instructed', 'ordered', or 'advised' depending on the context.
• The imperative mood is converted into the infinitive form by using 'to' + base verb ('to fasten').
• The second-person possessive pronoun 'your' changes according to the object 'passengers' into the third-person plural 'their'.
• Therefore, option A is grammatically and contextually correct.