Answer & Solution
Obtained from cinchona: Quinidine is derived from the bark of the cinchona tree.
O stereoisomer of quinine: Quinidine is an optical isomer of quinine, meaning they have the same molecular formula but different spatial arrangements.
An antiarrhythmic used in cardiac arrhythmia: Quinidine is used as an antiarrhythmic agent to treat cardiac arrhythmias.
Therefore,
Quinidine = All of the above
.