In the circuit below, the light dependent resistor (LDR) receives light from the LED. The LDR has resistances of 5 kΩ and 500 Ω under dark and illuminated conditions, respectively. The LED is OFF at time t < 0. At time t < 0 s, the switch S1 is closed for 1 ms and then kept open thereafter. Assuming zero propagation delay in the devices, the LED

• A. turns ON when S1 is closed and remains ON after S1 is opened
• B. turns ON when S1 is closed and turns OFF after S1 is opened
• C. turns ON when S1 is closed and toggles periodically from ON to OFF after S1 is opened
• D. remains OFF when S1 is closed and continues to remain OFF after S1 is opened