Just to supplement @Thiago's valid answer.
Transactions can't be directly cancelled or upgraded. The only thing you can do is send a new transaction with the same nonce but with higher gas price. If your new transaction get mined first (as it probably will as it has higher gas price) then the old transaction becomes obsolete as it has the same nonce.
Looking at your transaction, you have set a gas price of 4 gwei.
Though not very high for current traffic, this should eventually get picked up.
You can check gas prices and traffic on Etherscan Gas Tracker. That could help you decide if you want to pay a lower fee and wait longer for your transaction to be mined, or pay a higher fee to include it faster.
Yes, this is possible. It depends on the order of the transactions within the block itself. If you look at the Position tag of this transaction, you will see that it was the 144th transaction in that block.
In your case, you would want the A->B transaction to be ordered before the B->C transaction.
With that said, you cannot determine the order of the ...