Why Are the Dramatic Improvements with L-DOPA Often Short-Lived for Parkinson's

Multiple Choice

Why are the dramatic improvements with L-DOPA often short-lived for Parkinson's patients?

A) Eventually the neurons are unable to synthesize dopamine.
B) Though production of dopamine increases, overall too many neurons die off.
C) L-DOPA ceases to eliminate the overproduction of dopamine.
D) Over time L-DOPA becomes toxic to neurons.