Correct option is D
Cellulosic electrodes are widely used in welding because they provide deep penetration and fast welding speeds. However, they produce high levels of hydrogen gas during the welding process. This hydrogen can get trapped in the weld metal and cause hydrogen-induced cracking, especially in high-strength steels.
High-strength steels are more sensitive to such defects, making cellulosic electrodes unsuitable for these applications. Other options are incorrect because the main issue is not coating thickness, slag formation, or voltage requirements, but the presence of hydrogen.
Thus, due to the risk of cracking and reduced weld integrity, these electrodes are avoided for high-strength materials.
