Answer:
A). To emphasize the vast size of the desert.
Step-by-step explanation:
Word-choice always plays a significant role in conveying the intended meaning precisely and effectively to the readers. In the given excerpt, the word 'stretch' is deliberately employed to highlight the 'extensive size of the desert' ranging from 'the coast of the Red Sea in the east to the Atlantic Ocean in the west.' This helps convey the enormous area covered by this desert and the vastness of its size. Thus, option A is the correct answer.