Answer:
It was impure.
Step-by-step explanation:
"The Strange Case of Dr. Jekyll and Mr. Hyde" is written by Robert Louis Stevenson. It is a Gothic Novella.
The novella is about the dual nature of Dr. Jekyll. Dr. Jekyll, to separate his good side from the bad one, created a potion. With the help of this potion, he can transform himself from good Dr. Jekyll to evil Mr. Hyde.
The first batch of the potion or the drug that Dr. Jekyll created to transform himself, worked because it was impure. And this information we can get in the full statement of the case that Henry Jekyll wrote.
So, the correct answer is that the first batch of the drug worked because it was impure.