In a 555 timer, three 5 kΩ resistors provide a trigger level of ________.

• 1/4 VCC and a threshold level 1/2 VCC
• 1/3 VCC and a threshold level 3/4 VCC
• 1/3 VCC and a threshold level 2/3 VCC
• 1/4 VCC and a threshold level 2/3 VCC