Final answer:
Diminished rigidity is an indication that the medication levodopa/carbidopa is effective in managing the symptoms of Parkinson's disease.
Step-by-step explanation:
The medication levodopa/carbidopa is commonly prescribed for individuals with Parkinson's disease to help manage their symptoms. One of the primary motor symptoms of Parkinson's disease is rigidity, which refers to muscle stiffness and resistance to movement. Therefore, if a nurse observes diminished rigidity in a client who has been taking levodopa/carbidopa, it suggests that the medication is effective in improving their symptoms.