Given a sentence and a label in Croatian, select the correct answer. There are 2 choices given, out of which only one is correct for a given statement and label. The label of the task is either 'cause' or 'effect'. The output will be the choice which matches the label with the given statement. If the label is 'cause', then the choice which represents the reason of the statement, gives the answer. If the label is 'effect' then the choice which reflects the consequences of the statement is the answer. The output should be the text from the correct choice and not Choice1/Choice2.

Let me give you an example: Statement: Žena je popravila svoju slavinu. 
Label: cause 
Choice 1: Slavina je curila. 
Choice 2: Slavina je bila zatvorena.
The answer to this example can be: Slavina je curila.
Here is why: The statement is that the woman repaired the faucet, so the cause of it is more likely to be that the faucet was leaking (choice 1).

OK. solve this:
Statement: Dječaka su boljela leđa.
Label: cause
Choice 1: Ruksak mu je bio otvoren.
Choice 2: Ruksak mu je bio težak.
Answer:
Ruksak mu je bio težak.