The correct answer is option (B):
RQSP
The correct answer is RQSP. Let's break down why this sequence creates a coherent and meaningful sentence:
* **R: Going dark has its uses, Earth Hour:** This introduces the subject, "Earth Hour," which is a specific event. This is a good starting point.
* **Q: As it is called, will not reverse global warming:** This phrase clarifies what "Earth Hour" *is called* and then sets up a negative point about its effectiveness ("will not reverse global warming"). The "it" in "As it is called" refers to Earth Hour.
* **S: But it is a good way to raise awareness about:** The word "But" smoothly transitions from the negative point in Q to something positive about Earth Hour – that it's good for raising awareness.
* **P: The environmental problems the world is facing:** This phrase completes the thought by specifying what Earth Hour raises awareness *about*: the world's environmental problems.
Putting it all together, the sentence reads: "Going dark has its uses, Earth Hour, as it is called, will not reverse global warming, but it is a good way to raise awareness about the environmental problems the world is facing." This sequence creates a logical flow of ideas, starting with the subject (Earth Hour), explaining what it is and its limitations, and then highlighting its positive aspect. The other options do not form a sensible and complete sentence.