In each of the following questions one sentence has been given. Each sentence has two blanks. From the options given below the sentence, pick the pair of words that fits into both the blanks respectively to make the sentence contextually meaningful and mark the letter corresponding to it as your answer.

Plowing an entire field is _____________ toilsome, but even _____________ it is hard work farmers have to do it all the time.

The correct option is endlessly, then.

Let's analyze the sentence structure and context step-by-step to understand why this pair of words fits best into the blanks.

Sentence: "Plowing an entire field is _____________ toilsome, but even _____________ it is hard work farmers have to do it all the time."

Step 1: Analyzing the First Blank
The word "toilsome" is an adjective meaning extremely laborious or involving heavy, hard work. We need an adverb to intensify "toilsome".
- "Endlessly" is an adverb meaning continuously or infinitely, which appropriately modifies "toilsome" to emphasize that plowing a field feels like unending, tiring labor.

Step 2: Analyzing the Second Blank
The phrase "even __________" forms a conjunctional phrase modifying the clause that follows ("it is hard work...").
- Using "then" creates the conditional emphasis: "even then" (meaning "even in that case" or "despite that fact"). Thus, "even then it is hard work farmers have to do it all the time" expresses that despite how endlessly tiring it is, farmers must perform this task constantly.

Therefore, the word pair endlessly, then completes the sentence so that it is grammatically correct and contextually meaningful.