Choose an appropriate word from the options to suitably fill the blank in the sentence below so that the sentence makes sense, both grammatically and contextually.
We _______ finished reading at least half of the novel by the end of this week.
The blank should be filled with 'will have' which is the future perfect tense, which is used for actions that will be completed before some point in the future. The format is: will have + [past participle]
The rest of the options are cancelled as their tenses are wrong.
Hence the correct answer is option 1.