Select the most appropriate option to fill in the blank.

It is quite tough to ______ which candidate will win the presidential elections.

predict

The most appropriate option to fill in the blank is predict.

The sentence is about the difficulty of predicting which candidate will win the presidential elections. The word "predict" means to make a statement about what will happen in the future, based on current knowledge and evidence. It is the most appropriate word to use in this context because it accurately describes the task of predicting the outcome of an election.

The other options are not as appropriate.

• Pretend means to make believe or to act as if something is true, even though it is not. This does not make sense in the context of the sentence because no one is pretending to know who will win the election.
• Elect means to choose someone to hold a position of authority, usually by voting. This does not make sense in the context of the sentence because the speaker is not choosing the candidate, they are trying to predict who will be chosen by the voters.
• Argue means to give reasons for or against something, especially in a heated or angry way. This does not make sense in the context of the sentence because the speaker is not arguing about who will win the election, they are simply trying to predict the outcome.