Which of the following statements are correct for portable step-ladders?1. Used on working platforms to gain height above the protected edge2. Used in the fully opened position 3. Should be of a length that ensures a person's feet are not positioned any higher than the second top rungSelect the correct answer using the codes given below:

• A. 2 and 3 only
• B. 1 and 3 only
• C. 1 and 2 only
• D. 1, 2 and 3