Hello there! We can solve this one by one!
-1/4 = -2/8
-3/4 = -6/8
-2/8 - 3/8 = -5/8
-5/8 - 6/8 = -11/8
-11/8 - 7/8 = -18/8
-18/8 can be reduced by 2, we will result in -9/4.
-9/4 as a mixed number is -2 1/4.
Your final answer is D, or -2 1/4. Hope this helps!