Name the company associated with preparation and marketing of humulin on large scale in world.

Explanation

### Step-by-Step Solution:

1. **Understanding Humulin**:
- Humulin is a form of insulin that is synthesized from human sources. It is produced by taking pancreatic cells and synthesizing the insulin chains (A chain and B chain) separately.

2. **Synthesis Process**:
- The A chain and B chain of insulin are separated, purified, and then joined together using disulfide bridges to form the active form of Humulin.

...