[General] Quarantine can be used both as a.....

[Silverobama]

I wrote the following sentences.

a) Quarantine can be used both as a verb and a noun.
b) Quarantine is both a noun and a verb.

I used it when telling some beginners who just started to learn this language. Are they both natural?

 

[Rover_KE]

Use a), because it's not a verb and a noun at the same time.

In writing, 'quarantine' should be in quotation marks.

 

[jutfrank]

Use a), because it's not a verb and a noun at the same time.

I actually strongly agree with this view but the traditional, I dare say 'orthodox' view is that it is both at the same time, at least when it's out of context.