Final answer:
The correct answer is option C. "Travelled" should be corrected to "traveled."
Step-by-step explanation:
The correct answer to this question is option C. "Travelled" should be corrected to "traveled."
In American English, the preferred spelling is "traveled" with one "l" while in British English, it is spelled as "travelled" with two "l"s. Since the question does not specify a particular English dialect, we can assume it follows American English rules.
For example, the sentence should be rewritten as:
"The explorers became thirstier and their vision blurred as they traveled further across the arid desert and tried to make their way to the oasis."