During endotracheal intubation, the vocal cords are not visible. Which instrument can help guide placement of the tube into the trachea?

Correct option is B

A gum-elastic bougie is used when cords are not clearly visible. The bougie slides into trachea and endotracheal tube is railroaded over it.
Explanation of options: (a) ✘ Laryngoscope alone cannot help if cords are invisible. (b) ✔ Correct; bougie is used as introducer in difficult intubations. (c) ✘ Magill’s forceps are for NG tube guidance, not ET intubation. (d) ✘ Oropharyngeal airway prevents tongue fall, not tube placement.