Which symptom would likely be an indicator of Parkinson's disease?

Tremors and rigidity are hallmark symptoms of Parkinson's disease, making this option the most indicative of the condition. Parkinson's disease is a neurodegenerative disorder that affects movement, and the presence of resting tremors (shaking that often occurs when the person is not actively moving) is one of the most recognizable signs. Additionally, rigidity, which refers to stiffness in muscles, also significantly impacts a person's ability to move smoothly and can lead to other issues like pain and decreased mobility.

In contrast, while the other options can present with various medical conditions, they are not specific indicators of Parkinson's disease. For instance, excessive weight loss could be a sign of multiple health issues, including other neurological or metabolic disorders. Severe headaches typically point to migraine or other types of headache disorders and do not correlate with the primary symptoms associated with Parkinson's. Similarly, a rapid heart rate may indicate stress, anxiety, or cardiovascular issues but does not relate specifically to Parkinson's disease symptoms. Thus, tremors and rigidity are the defining symptoms that align with the diagnosis of Parkinson's disease.