Select the most appropriate choice to fill in the blank.
The country's politics ________________ complex, with more than ten parties competing for
power.

Correct option is C

The word that can be filled in the blank is ‘is’ to make the sentence grammatically and contextually correct. • Is is the correct form of the verb to indicate that the politics of the country are a singular subject despite being plural in form. Grammatical Rule involved: Subject-verb agreement - When discussing the field of politics, it takes a singular verb. • In this context, ‘is’ appropriately denotes the singular nature of the political system.
Meanings of other given words:
• Are - the plural form; incorrect here. • Am - incorrect usage; does not match the subject. • Were - past tense; not applicable. • Thus, only ‘is’ maintains grammatical correctness.