question 15 / 25 which is true of mobile ladder locking mechanisms select the best answer: must be properly…

question 15 / 25 which is true of mobile ladder locking mechanisms select the best answer: must be properly engaged before use may be spring loaded may require manual activation all of the above none of the above
Answer
Brief Explanations:
Mobile ladder locking mechanisms must be properly engaged before use to ensure safety. They may be spring - loaded for convenience and ease of operation, and also may require manual activation depending on the design. So all the individual statements are true.
Answer:
D. All of the above