**Core Concept**
The discovery of the insulin amino acid sequence and molecular structure is a crucial milestone in understanding the physiology of insulin, a hormone produced by the pancreas that regulates blood glucose levels.

**Why the Correct Answer is Right**
Frederick Sanger was awarded the Nobel Prize in Chemistry in 1958 for determining the amino acid sequence of insulin. This achievement was a significant breakthrough in understanding the molecular structure of insulin, a protein hormone composed of two polypeptide chains. Sanger's work involved the use of paper chromatography and other techniques to sequence the amino acids in insulin, providing valuable insights into its structure and function. His discovery paved the way for further research into the molecular mechanisms of insulin action and its role in glucose metabolism.

**Why Each Wrong Option is Incorrect**
**Option A:** Banting and Macleod were awarded the Nobel Prize in Physiology or Medicine in 1923 for the discovery of insulin, but not for determining its amino acid sequence or molecular structure.
**Option C:** Charles Best was a co-discoverer of insulin with Banting and Macleod, but he was not involved in the sequencing of insulin's amino acid sequence.
**Option D:** Paul Berg was a Nobel laureate in Chemistry in 1980 for his work on the discovery of DNA recombination, but he had no involvement in the sequencing of insulin's amino acid sequence.

**Clinical Pearl / High-Yield Fact**
The discovery of insulin's amino acid sequence and molecular structure has far-reaching implications for our understanding of glucose metabolism and the treatment of diabetes mellitus. This knowledge has led to the development of insulin analogs with improved pharmacokinetic profiles, which are used in the management of diabetes.

**✓ Correct Answer: B. Sanger**