Select the most appropriate option to substitute the highlighted segment in the given sentence.
Learning a new language can be all challenging and rewarding.

Correct option is A

✔️ Correct option: (a) both challenging and rewarding
Correct sentence: Learning a new language can be both challenging and rewarding.
Explanation:
The sentence requires a correlative conjunction pair. “Both...and...” is used to link two positive qualities.
Grammatical rule used:
Correlative conjunctions like both...and, either...or, neither...nor must be used in pairs and maintain grammatical parallelism.
✦ Hindi explanation: जब दो विशेषणों या गुणों को जोड़ना हो, तो “both...and” का प्रयोग किया जाता है, जैसे: “both interesting and helpful.”
Meanings of all options:
· (a) both challenging and rewarding – correct parallel structure ✅
· (b) neither challenging and rewarding – incorrect correlative use ❌
· (c) whether both challenging and rewarding – ungrammatical ❌
· (d) all both challenging or rewarding – redundant and incorrect ❌