Final answer:
The correct word to complete the fill-in-the-blank question is 'knowing', which is used to indicate the speaker took action based on their knowledge about the listener's food preferences.
Step-by-step explanation:
The correct answer to the fill-in-the-blank question is option B, 'knowing'. The complete sentence should read: 'Knowing you don't like seafood, I've cooked some chicken too.' This construction uses 'knowing' as a participle to provide a reason for the action in the main clause, which is a common usage in English to express that someone has taken an action based on their knowledge of a situation.