Final answer:
Linus Pauling was the first to propose the correct model of the alpha helix, which is a fundamental component of protein structure. Pauling's extensive research in structural chemistry laid the groundwork for understanding protein architecture.
Step-by-step explanation:
The individual who was the first to propose a correct model of the alpha helix was a) Linus Pauling. In the 1950s, Linus Pauling was at the forefront of research in structural chemistry and is especially renowned for his discovery of the secondary structure of proteins using X-ray crystallography. While Pauling initially proposed a triple-stranded model of DNA that turned out to be incorrect, his work on protein structures was groundbreaking, including the discovery of the alpha helix structure. It is also important to note that X-ray diffraction methods played a significant role in the work of other scientists like Rosalind Franklin, whose high-quality X-ray diffraction images of DNA were pivotal in revealing its double-helix structure, leading to the acclaimed discovery by Watson and Crick of the double stranded structural model of DNA.