Concept:The answer must be the word that is most nearly opposite in meaning to the underlined word and still fits naturally in the sentence.
Explanation:The underlined word describes someone who is hardworking or diligent.
Therefore, its opposite would be someone who avoids work or effort.
From the options, the word "lazy" exactly conveys this opposite meaning.
"Patient" and "slow" are not opposites of hardworking.
"Casual" means relaxed or informal, not the correct opposite here.
Only "lazy" gives the required contrast while fitting the gap correctly.
Answer:C. lazy