Option 1 -> An apostate is someone who renounces or abandons their religious or political beliefs.
Option 2 -> An alchemist is someone who practices alchemy or transforms things, unrelated to abandoning beliefs.
Option 3 -> An anarchist advocates for absence of government authority but doesn't mean someone who rejects beliefs.
Option 4 -> An apostle is a passionate supporter of beliefs, the opposite of someone who rejects them.
Hence, Option 1: apostate -> The word "apostate" specifically refers to a person who renounces or rejects their religious, political, or philosophical beliefs, making it the perfect fit for describing Dr. Kevin who has rejected all his religious and political beliefs -> correct