Waiting for bus is a _________ experience.

Correct option is B

The correct answer is (b) killing.
Explanation:
· "Killing" is an adjective describing the noun "experience".
· Correct sentence: Waiting for the bus is a killing experience.
Grammatical Rule Used (English):
· "Killing" is used as a participle to describe a noun.
· Structure: Gerund/Participle + Noun.
व्याकरणिक नियम (Hindi):
· "Killing" (मार डालने वाला/कष्टदायक) विशेषण के रूप में प्रयोग किया जाता है।
· संरचना: वर्तमान कृदंत (Present Participle) + संज्ञा।