A is the correct answer because the equation matches option A.
(-2 1/2) + (-3 1/4)
The minus sign in -2 1/2 shows that the submarine descendedand then descendedagainwith the addition sign. Though the addition sign can mean that it ascendedits incorrect.
Say if you have 11% and you want to turn it into a fraction all you got to do is put 11 as your numerator and 100 as your denomanator. Or if it is 75% you have to do the same but simplify and its would make 15/20 then simplify again and its 3/4