Who worked on the king's resting place?

Ответ: craftsmen working for many years

В тексте сказано: "Their kings were very important, and when they died, workers built special tombs for them. One of the most famous tombs looked like a huge triangle. It took many people and a very long time to build it."

Из этого следует, что гробницы строили работники/мастера, и это занимало много времени.

Ответ: craftsmen working for many years