The word 'penalties' makes the sentence meaningful, suggesting that the consequences of certain actions are negative. This fits the context of actions that could result in penalties.
- Option (a) 'gifts' would not make sense in the context of this sentence.
- Option (b) 'lucrative' would suggest a financial gain, but does not align with the intended meaning.
- Option (c) 'casualties' implies harm or death, which doesn't suit the context either.
Thus, 'penalties' is the most fitting word.