नदियों को प्रदूषित नहीं करना चाहिए।
Step 1: Understanding the Hindi Sentence:
The sentence "\begin{hindi}नदियों को प्रदूषित नहीं करना चाहिए।\end{hindi}" (Nadiyon ko pradushit nahin karna chahiye) expresses advice or a moral obligation. The key word here is "\begin{hindi}चाहिए\end{hindi}" (chahiye), which translates to the modal verb 'should' or 'ought to'. The sentence is in the passive sense ("rivers should not be polluted" by people).
Step 2: Analyzing the English Options:
- (A) The rivers are not be polluted: Grammatically incorrect. It should be 'are not polluted' (simple present passive).
- (B) The rivers were not be polluted: Grammatically incorrect. It should be 'were not polluted' (simple past passive).
- (C) The rivers would not be polluted: 'Would' expresses a conditional possibility, not an obligation. Incorrect.
- (D) The rivers should not be polluted: This correctly uses the modal verb 'should' to express the obligation or advice in 'chahiye'. The structure 'should not be + past participle' is the correct passive form.
Step 3: Final Answer:
The most suitable translation is The rivers should not be polluted.
मैं एक पत्र लिखने जा रहा हूँ।
सच्ची मित्रता दुर्लभ है।