Answer: D/ 6.
Step-by-step explanation: First, you have to do division to find out how many minutes = 1 nautical mile.
378 divided by 21= 18.
Then, you would do 108 divided by 18, to find out the answer; 6.
To double check your work, get the answer you got and multiply it by the minutes per mile which is 18.
18 x 6 = 108.
Therefore, it will be 6 nautical miles in 108 minutes.