No way to use conditional logic based on a multiple choice field?

[Loki44]

There doesn't seem to be an obvious way to display a field based on the input of a conditional logic field.

for instance if you have a multiple choice field: "What are you interested in?" with options "a" and "b".

and then want to display a field "where" only if the user has selected "a", there doesn't seem to be an obvious way to do this.

Simply entering "a" into the conditional logic box results in the field still being hidden.