"The soup is not delicious."
There is also inconsistency with regard to formality levels. There should be some indication in the question (maybe a separate phrase or sentence to set the scene) as to which verb ending is called for. Otherwise, all politeness levels should be accepted.
The use of topic particles vs subject particles is very confusing for many students of the Korean language. It would be nice if DL could use exercises to clarify the usage of each. At present, the presentation throughout the course is very inconsistent.