Select the most appropriate collocating word to fill in the blank.

After having understood the ill effects, he said he would ______ drinking alcohol.

quit

The most appropriate collocating word to fill in the blank is quit.

The word "quit" means to stop doing something, especially something that is harmful or addictive. It is the most appropriate option in this context because it conveys the idea that the person is making a conscious decision to stop drinking alcohol.

The other options do not make sense in the context of the sentence.

• "Finish" means to complete something. It does not make sense to say that the person would finish drinking alcohol.
• "Close" can mean to stop something, but it is not as strong as "quit".
• "Terminate" means to end something completely. It is too strong of a word to use in this context.