Concept:"Arduous" means difficult and tiring. We must choose its opposite, or antonym, among the given pairs.
Explanation:In the sentence, "arduous" describes Arvind's task as one requiring great effort and stamina.
So the correct pair should mean the opposite: easy and requiring no hard work.
Option A, "strenuous and exacting", suggests effort and precision, so it is a synonym.
Option B, "onerous and overbearing", means burdensome and oppressive, also not opposite.
Option C, "difficult and exacerbating", is close in meaning and cannot be the antonym.
Option D, "easy and effortless", directly contradicts "arduous" by meaning not difficult and free from effort.
Answer:D. easy and effortless