Concept:
Crops are classified based on their primary use such as food crops, fiber crops, oil crops, etc. Fiber crops are grown mainly for obtaining fibers used in textiles, ropes, and other materials.
Step 1: Understanding Fiber Crops
• Provide raw material for textiles.
• Examples: cotton, jute, sunnhemp.
Step 2: Evaluating Options
Lentil (A)
• Pulse crop
• Used as food (protein source)
Sorghum (B)
• Cereal crop
• Used for food and fodder
Sunnhemp (C)
• Fiber crop
• Used for making ropes, twine, and cordage
Sesame (D)
• Oilseed crop
• Used for edible oil
Step 3: Final Identification
• Only Sunnhemp belongs to fiber crop category.
Final Conclusion:
\[
\boxed{\text{Sunnhemp}}
\]