all you need to do is take 1,973 and subtract 99 from it to get 1,874.
hope this helps
The answer you'd be looking for is 2,072ft.
The reason 2,072ft is the answer, is because the 99ft are below sea level, making it negative, while 1,973ft are above sea level, making it positive. So, you add 99 to 1,973 to account for the entire difference between the 2. Therefore making 2,072ft the answer.
I hope this helps!