A beacon's brightness follows the one-cycle table and then repeats. Which statement correctly extends the relationship?

Answer and derivation

Correct answer: B

The period is 4 seconds, so the value at 6 seconds matches the value at 2 seconds: 8.

1. The rows at 0 and 4 seconds mark matching cycle endpoints.
2. Thus the relationship has period 4 seconds.
3. Because $6=2+4$, the brightness is 8.

Why the other options fail

A

This repeats the start one second too late.

B

Correct: 6 seconds is two seconds into the next four-second cycle.

C

Seven seconds corresponds to the three-second row, whose value is 5.

D

Eight seconds starts a new cycle, so the value is 2.

Common misconception: A cycle's two matching endpoints are not two different observations within the repeating block.

China/AP bridge: China-course bridge: periodic sequences extend familiar repeating patterns; AP newly expects students to construct a representation from one cycle; unlike copying rows indefinitely, use the least period; a common pitfall is double-counting an endpoint.