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

A
strengthen the main deck by placing pillars underneath it in the tween-decks
B
package the cargo in wooden crates so it will not damage the deck
C
distribute the weight of the cargo by placing fore-and-aft planks on the main deck
D
weld pad eyes on deck in proper position to secure the cargo
E