लेखनविषयक नियमानुसार योग्य असलेला पर्याय निवडा.

The correct answer is Option B (दूरबीण).

Key Points:
• The key concept is identifying correct spelling based on Marathi orthographic rules.
• The word for binoculars is composed of 'दूर' (far) + 'वीक्षण/बीण' (sight).
• In standard Marathi orthography, it is often written as 'दूरबीण' with a long 'दू' (दीर्घ उकार) and long 'बी' (दीर्घ वेलांटी). Option 2 correctly uses this standard form accepted by the examination key.
• 'दुर्बीण' is a common pronunciation variant, but the formally accepted root-based spelling in this exam's context is 'दूरबीण'.
• Key Takeaway: The officially accepted spelling in this context is 'दूरबीण' (long 'ू' and long 'ी').