Question

The role of enzymes in biological systems is to catalyze chemical reactions. In 1894, chemist Emil Fischer proposed the lock and key analogy of enzyme action. This analogy explains the specific action of an enzyme with a single substrate. Compare the two models seen here. How do they BOTH represent the lock and key analogy?

Answer 1

Provided that there's no diagram, most molecules have particular areas on the molecules, called the "active area" that act as a lock to a particular substrate's molecular structure, providing the key. 
An enzyme's active area is only able to be "unlocked" by a certain substrate's "key". 

Answer 2

The answer is A) Only a specific substrate fits into the active site of the enzyme.