The per hectare seed rate of tobacco is:

Correct option is C

The per-hectare seed rate for tobacco is generally 2.5 to 5 kg/ha, with 3 kg/ha often cited as an optimum for most types, though specific needs vary; for example, Nicotiana tabacum might use 3 kg/ha, while N. rustica could require up to 6 kg/ha, with seeds typically sown in nurseries for transplanting. 

Key Points:

• General Range: 2.5 - 5 kg/ha (kilograms per hectare).
• Common Recommendation: 3 kg/ha for most varieties.
• Specific Varieties: 3 kg/ha for N. tabacum (common tobacco) and 6 kg/ha for N. rustica (rustic tobacco).
• Seed Size: Tobacco seeds are very small (about 10,000 per gram), requiring careful sowing in nurseries. 

Why the Variation?
The exact seed rate depends on the tobacco type (N. tabacum, N. rustica, etc.), local climate, and soil conditions, as these factors influence germination and seedling survival.