Answer:
superfluous
Step-by-step explanation:
Superfluous means unnecessary. Replacing the phrase "really unnecessary" with it's synonym, superfluous will not change the meaning of the sentence. Hypothetical is something that could happen but hasn't actually happened. It's an "if" type situation. Compulsory is a requirement. This is the opposite of really unnecessary. Conservative basically means traditional. These other options would change the overall meaning of the sentence.