Improve the highlighted part of the sentence.
He sand the wooden with coarse sandpaper.

The correct substitution of the highlighted part is (b) sanded the wood.
Explanation:
1. "Sand" in this context refers to the action of smoothing or polishing wood, so the correct verb tense is required.
2. The original sentence is in the past tense, so "sanded" is the correct past form.
3. "Sand the wood" (option c) is in the present tense and doesn't match the past context.
Hindi Explanation: "Sand" का अर्थ है लकड़ी को चिकना या पॉलिश करना। वाक्य भूतकाल में है, इसलिए सही उत्तर "sanded the wood" होगा।
Corrected Sentence: He sanded the wood with coarse sandpaper.