Which of the following is a classical presentation of neurotoxicity resulting from manganese exposure?

The classical presentation of neurotoxicity resulting from manganese exposure is characterized by parkinsonism symptoms. Manganese is a metal that, when accumulated in the body—particularly the brain—can lead to a range of neurological issues that are similar to Parkinson's disease. This includes symptoms such as tremors, rigidity, bradykinesia (slowness of movement), and postural instability.

In contrast, while cognitive impairment can occur with manganese toxicity, it is not the most distinct or classical sign associated with this specific type of exposure. Panic attacks and memory loss may arise from various other conditions or exposures, but they are not typically characteristic of manganism, which primarily manifests with parkinsonian features. Therefore, the most indicative and classical representation of neurotoxicity from manganese is indeed the development of parkinsonism symptoms.