PS Form sec**05-Q9

[hoojjj]

Eight light bulls numbered 1 through 8 are arranged in a cricle as shown below. The buls are wired so that "every thrid bulb, counting in a clockwise direction, flashes until all bulbs have flashed once. If the bulb numbered 1 flashed first, which numbered bulb will flash last?
A)2 B)3 C)4 D)6 E)7
Ans:D
Why?
看不懂題目 不知道它是怎麼個亮法???

1
8 2
7 3
6 4
5

[Pufa]

不好意思，可不可以把選項答案post上來。
讓沒有題目的朋友也可以幫你解答~