Final answer:
The most important initial information to obtain in a patient showing possible stroke symptoms is the time when symptoms started, as prompt treatment is crucial for recovery.
Step-by-step explanation:
The most important initial information to obtain about a 66-year-old female presenting with acute onset of confusion, slurred speech, and an inability to move her right arm and leg is c) Time when symptoms started. This is crucial because treatment options and outcomes for conditions such as a stroke are time-dependent. The sooner a patient receives treatment, the better the chances of recovery. The mnemonic FAST highlights the urgency in recognizing stroke symptoms, emphasizing that 'Time' to call for help is critical when identifying sudden neurological function losses.