This is a microfilament inhibitor

The correct option is cytochalasin-B.

Step-by-Step Explanation:

1. Understanding Microfilaments:
Microfilaments, also known as actin filaments, are key components of the eukaryotic cytoskeleton. They are composed of actin polymers and play vital roles in cell motility, structure, cytokinesis, and intracellular transport.

2. Mechanism of Cytochalasins:
Cytochalasin-B is a cell-permeable fungal metabolite. It binds specifically to the barbed (plus) ends of actin microfilaments. By capping these ends, it prevents the addition of new actin monomers, thereby inhibiting both microfilament polymerization and elongation.

3. Analyzing the Other Options:
- Cinchonine: This is an alkaloid isolated from cinchona bark, primarily known for its antimalarial properties, not as a cytoskeleton inhibitor.
- Aspirin: This is a nonsteroidal anti-inflammatory drug (NSAID) that acts by inhibiting cyclooxygenase (COX) enzymes to reduce inflammation and pain.
- Colchicine: This is a medication that inhibits microtubule polymerization by binding to tubulin, rather than affecting actin microfilaments.

Therefore, cytochalasin-B is the specific microfilament inhibitor among the given choices.