Explanation:
The correct answer is option 'C' - put off.

- To put off means to delay or postpone something.
- In this context, the trip had to be postponed because of the bad weather.
- The phrase "put off" is commonly used to refer to rescheduling or moving an event or activity to a later time or date.
- When the weather conditions are unfavorable or unsafe, it is sensible to put off a trip to ensure the safety and well-being of the individuals involved.

Example:
- The organizers decided to put off the picnic due to the heavy rainstorm.
- They had to put off the concert because the lead singer fell ill.

Incorrect options:
a) call off: This phrase means to cancel an event or activity entirely, often due to unforeseen circumstances or unavailability of resources. It is not suitable in this context because the trip was delayed, not canceled altogether.
Example: They had to call off the wedding due to a family emergency.

b) call out: This phrase means to summon or request someone to come forward or take action. It is not appropriate in this context as the trip was not called out or summoned.
Example: The teacher called out the student's name to answer a question.

d) take off: This phrase means to depart or leave, especially in the case of a vehicle or aircraft. It does not fit in this context as the trip was not initiated or started.
Example: The plane will take off in an hour.

Therefore, the correct answer is option 'C' - put off.