English grammar — participial clause for simultaneous action: Choose the correction that makes the sentence tense-consistent. Original sentence: "He found the gold coin as he cleans the floor." Select the best replacement for the highlighted part.

Given data

• Main clause in past simple: "He found…"
• Subordinate action is simultaneous and backgrounded.

Concept/Approach
Use a participial clause to show simultaneous action with past main clause: "He found … while cleaning the floor." This avoids a tense clash ("found" vs "cleans").

Option analysis
A. "as he had cleaned" → past perfect implies completion before finding; wrong meaning.B. "while he cleans" → present simple clashing with past simple.C. "which he is cleaning" → present progressive clash and relative clause not needed.D. "while cleaning" → concise, tense-consistent, and idiomatic. ✔E. No correction → original is inconsistent.

Corrected sentence
"He found the gold coin while cleaning the floor."

Final Answer
while cleaning