What does it mean to "shore up" the main deck for the stowage of deck cargo?

Correct Answer: Option A — strengthen the main deck by placing pillars underneath it in the tween-decks

Shoring up a main deck involves installing vertical pillars directly beneath the deck structure in the tween-decks to transfer concentrated deck cargo loads down to lower structural members, preventing structural deformation or failure in compliance with sound marine structural and cargo handling practices.