Answer
B, To dig out
Step-by-step explanation:
The treasure was buried DEEP into the sand, if they wanted to get it out, they would have to dig it. It's not A, because the treasure is deep in the sand and you can't just uncover it. And it doesn't take all day to uncover something. Its not C because they already found the treasure, now they have to dig it it out. It's not D either because getting things up makes no sense.