Spot the grammatical error in the sentence. Select the part (A–D) that contains an error; if the sentence is correct, choose ‘‘No error.’’ Sentence: At last the rain ceased and the sky was cleared by clouds and lightning.

Introduction / Context:
Error-spotting questions often test common preposition choices. Here, the clause describes the sky becoming free of something. In standard English, we say that a place or surface is ‘‘cleared of’’ unwanted things, not ‘‘cleared by’’ them.

Given Data / Assumptions:

• The event is complete: ‘‘the rain ceased.’’
• Target phrase: ‘‘the sky was cleared by clouds and lightning.’’
• Intended meaning: the sky became free of clouds and lightning.

Concept / Approach:
Use the pattern ‘‘clear + object + of + unwanted items.’’ Examples: ‘‘clear the desk of papers,’’ ‘‘the sky cleared of clouds.’’ The preposition ‘‘by’’ after a passive verb introduces the agent (who performs an action). Clouds are not the agents clearing the sky; they are the things removed. Hence ‘‘of’’ is required.

Step-by-Step Solution:
Identify verb–preposition pair: ‘‘was cleared by’’ → should be ‘‘was cleared of.’’Apply to both items: ‘‘… cleared of clouds and lightning.’’Final corrected sentence: ‘‘At last the rain ceased and the sky was cleared of clouds and lightning.’’

Verification / Alternative check:
Paraphrase: ‘‘Clouds and lightning cleared the sky’’ would suggest they acted as agents, which is illogical. Therefore ‘‘of’’ is the only idiomatic choice.

Why Other Options Are Wrong:

• A: Grammatically sound opening.
• B: Passive auxiliary ‘‘was’’ is fine.
• D: Completes the list; the error is already in C.

Common Pitfalls:
Confusing ‘‘cleared of’’ (removal) with ‘‘cleared by’’ (agent). The latter drastically changes the logic of the clause.

Final Answer:
cleared by clouds