$11.$ Identify the statement below that describes proof$-$of$-$work.

A$.$ Proof$-$of$-$work is a consensus mechanism by which miners compete to solve a challenging computational problem in order to create the next block on a blockchain

B$.$ Proof$-$of$-$work is a consensus mechanism in which miners prove that they have done work by staking currency in exchange for the right to write a block to the blockchain

C$.$ Proof$-$of$-$work is a consensus mechanism in which a group of delegates verify thar work has been done by miners before allowing them to create blocks