In the following sentence, the bracketed part is incorrect. Choose the option that best improves the bracketed part so that the sentence is grammatically correct. The doctor (has advice) him to take proper diet.

Introduction / Context:
Sentence improvement questions test your knowledge of correct verb forms and tenses in actual usage. In this sentence, the bracketed phrase has advice is wrong and needs to be replaced. Your job is to choose the option that makes the sentence correct and natural in standard English while keeping the intended meaning.

Given Data / Assumptions:
- Original sentence: The doctor (has advice) him to take proper diet. - Options: has advised, had been advised, was advised, No improvement. - The subject is the doctor and the object is him, and the sentence refers to a recent action with present relevance.

Concept / Approach:
The error arises from confusing the noun advice with the verb advise. The doctor gives advice, but the doctor advises someone. In present perfect tense, we use has or have plus the past participle of the verb. The correct past participle of advise is advised. Therefore, the doctor has advised him is the right structure. Options that change the voice or tense inappropriately will not convey the same meaning. We need an active voice present perfect construction to show that the doctor has already given the advice, and the effect remains relevant.

Step-by-Step Solution:
Step 1: Identify the intended meaning: the doctor has already given him advice about following a proper diet. Step 2: Recognise that has advice is incorrect because has requires a noun, but the rest of the sentence structure calls for a verb phrase. Step 3: Examine option A, has advised. This forms the present perfect tense, indicating that the advising has happened at some time before now with present relevance. Step 4: Examine option B, had been advised. This is past perfect passive voice and would mean that someone had advised him earlier, not necessarily the doctor mentioned as subject. Step 5: Examine option C, was advised. This is simple past passive and changes the focus from the doctor as subject to him as recipient. Step 6: Examine option D, No improvement. This cannot be correct, since has advice is clearly ungrammatical in this structure.

Verification / Alternative check:
Insert each option into the sentence. The doctor has advised him to take proper diet is grammatically correct and communicates that the doctor has given advice at some point before now. The doctor had been advised him is impossible because of the clash between active subject and passive form. He was advised to take proper diet removes the doctor as clear agent unless we rewrite the whole sentence. No improvement would keep the incorrect phrase has advice. Hence, has advised is the only choice that both corrects the grammar and keeps the original meaning with the doctor as subject.

Why Other Options Are Wrong:
Had been advised is wrong because it is in passive voice and past perfect, which does not fit with the doctor as the active subject in the given sentence. Was advised is wrong because it is simple past passive and would require restructuring of the subject and object to sound natural. No improvement is wrong because the original phrase has advice is not a valid verb construction and mixes noun and auxiliary incorrectly.

Common Pitfalls:
Learners sometimes confuse advice and advise because they sound similar. Advice is a noun, while advise is a verb. Examiners use this confusion to create traps. To avoid errors, remember simple sentences like My parents advise me and their advice is helpful. Also note typical structures like the doctor has advised me to rest, which use the present perfect tense correctly. Practising such patterns will help you quickly spot and correct mistaken forms in sentence improvement questions.

Final Answer:
The correct improvement is: The doctor has advised him to take proper diet.