Final answer:
The correct answer is option a) panoramic.
Step-by-step explanation:
When reaching the summit of a volcano, having endured a challenging hike, the sight that greets you is usually vast and all-encompassing. The correct word to fill in the blank in the sentence 'When we reached the top of the volcano, the (______) view was well worth the five-hour hike.' is panoramic.
This term describes an unobstructed and wide view of an extensive area in all directions. It is often used to describe broad, scenic vistas such as those seen from mountaintops or lookouts, providing a broad perspective that can capture the splendor of a landscape in a single gaze.