Explanation:

Let’s break it down, one by one:

- Anodyne means something that soothes or relieves pain; it’s actually harmless, not dangerous.

- Perilous is the one you want. It means full of danger or risk.

- Innocuous means not harmful or offensive, so totally the opposite of dangerous.

- Propitious is all about being favorable or indicating good chances; nothing risky here.

- Benign describes something gentle, kind, or harmless—again, not dangerous at all.

So, out of these, only perilous lines up directly with "dangerous." Good call.