In the following question, a sentence has been given in Active Voice. Out of the four alternatives suggested, select the one which best expresses the same idea in Passive Voice: "Scientists generally believe that small islands would sink."

Introduction / Context:
This question involves converting a reporting sentence with the verb "believe" from active to passive voice in a natural, formal style. The active sentence is "Scientists generally believe that small islands would sink." Examinations often prefer an impersonal passive structure for such sentences, beginning with "It is generally believed that ...". You must choose the option that correctly reflects this structure without distorting the meaning.

Given Data / Assumptions:

• Active sentence: "Scientists generally believe that small islands would sink."
• Subject: "Scientists".
• Reporting verb: "believe" in simple present.
• Adverb: "generally".
• Reported clause: "that small islands would sink."

Concept / Approach:
For sentences expressing general beliefs or opinions, English typically uses an impersonal passive form which shifts focus away from the group of people and toward the belief itself. The pattern is "It is generally believed that ...". Here, "believe" in simple present becomes "is believed" in passive. The adverb "generally" is placed before "believed", and the original that clause remains unchanged. Adding "by scientists" is optional but often included in exam style sentences to show the original agent group.

Step-by-Step Solution:
Step 1: Identify the main clause: "Scientists generally believe".Step 2: Convert this to impersonal passive: "It is generally believed".Step 3: Optionally include the agent: "by scientists".Step 4: Attach the that clause exactly as it is: "that small islands would sink".Step 5: Form the complete sentence: "It is generally believed by scientists that small islands would sink."

Verification / Alternative check:
Compare the two versions. Active: "Scientists generally believe that small islands would sink." Passive: "It is generally believed by scientists that small islands would sink." Both express exactly the same idea: there is a general belief among scientists about the fate of small islands. The tense remains present, the adverb "generally" stays, and the subordinate clause with "would sink" is unchanged. This confirms that option D is correct.

Why Other Options Are Wrong:

• Option A: "Small islands will sink is generally believed by scientists." This has incorrect word order and replaces "would sink" with "will sink", changing the nuance.
• Option B: "There is a general belief that small islands would sink." This removes explicit mention of scientists as the believing group. It is semantically close but not as precise as the required passive structure.
• Option C: "Small islands are believed to sink by scientists." This not only changes "would sink" to "to sink" but also sounds awkward in this context.
• Option E: "Scientists are generally believed that small islands would sink" is ungrammatical, because "believed" cannot take "scientists" as subject in this pattern.

Common Pitfalls:
Students often try to put the original object at the beginning and follow it immediately with "are believed", without checking whether the resulting sentence is natural and grammatically correct. In many reporting verb cases, the safest and most natural passive pattern is the impersonal "It is believed that ...". Recognising such patterns will help you avoid forced or incorrect word orders in the exam.

Final Answer:
The correct passive voice sentence is "It is generally believed by scientists that small islands would sink."