Correct Answer: one another
 

Solution : Option C 'One another,' is the correct answer.

Explanation:

• - The right answer to the fill-in-the-blank question is 'one another.'
• - We all know that the term "one another" refers to a mutual relationship between more than two people or things.
• - Because there are three political parties in the stated question, we should use one another..
• - Based on the information presented above, it is evident that 'one another' is the correct answer.
• As a result, the right sentence is:During the election, the three major political parties were accusing one another of not following the COVID-19 guidelines.
• Additional Information - the word each other refers to the mutual relationship between two persons or things.