Institution: জাতীয় কবি কাজী নজরুল ইসলাম বিশ্ববিদ্যালয় (JKKNIU) Exam: ক ইউনিট || জাতীয় কবি কাজী নজরুল ইসলাম বিশ্ববিদ্যালয় || 2013
Topic: Synonyms, Subject: English Grammar (ইংরেজি গ্রামার)

Best Answer Explained in Below-:

The synonym of 'contaminate' is indeed 'adulterate' (option C). To contaminate means to make something impure or polluted by introducing unwanted or harmful substances. This action can occur in various contexts, such as food, water, or the environment. Similarly, 'adulterate' refers to the act of making something poorer in quality by the addition of another substance, often one that is inferior or harmful.

In both terms, the underlying concept revolves around compromising the purity or integrity of a material. For instance, in food production, if a high-quality ingredient is mixed with a cheaper, inferior one, that food item is said to be adulterated. This is similar to contamination, where harmful foreign substances may enter a pure product, affecting its safety and quality.

In contrast, options A (revel), B (purify), and D (clean) do not align with the meaning of 'contaminate.' 'Revel' means to enjoy oneself in a lively way, 'purify' means to make something pure, and 'clean' refers to removing dirt or impurities. Therefore, 'adulterate' stands out as the most accurate synonym for 'contaminate.'