Which of the following statements are correct in case of vertical intermediate stiffeners?1. These are required only when the ratio of web depth to thickness is greater than 150.2. They should be provided throughout the length of beam at spacing less than 1.5 times web depth.3. These can be fitted between flanges with clear gaps at top and bottom.

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