Answer: The answer is concern
nuisance is to pest as worry is to ?
First, define the relationship between nuisance and pest.
Nuisance is a synonym of pest.
You need to find the answer choice that has the same relationship with worry.
Worry is a synonym of ?
Now try out each answer choice.
Worry is a synonym of anxious? No.
Worry is a synonym of confidence? No.
Worry is a synonym of concern? Yes.
Worry is a synonym of a failure? No.
Complete the analogy with the word concern.