It's true and the intent of such questions is to analyze how you can analyze and asses the meanings of a paraphrased complex sentence. Despite rumors means (however many believe it but.....)
The passage said "Despite rumours to the contrary, skinks are all completely harmless to humans, being neither poisonous nor able to inflict damage with their teeth" not what you're saying. This means in spite of the opposite effect from what has been stated or what is expected. What has been stated in this case is "being harmful" and NOT being "poisonous". The answer here is NOT GIVEN.