Using the two coordinates you can find the equation
------------------------------------
Find slope first
Slope

0 - 3 = -3
-------
-4 - 0 = -4
--------------------------------------------------
Simplify -3/-4
3/4
-----------------------------------------------------------
Your slope is 3/4 and the Y-intercept as mentioned in the question is "3"
----------------------------------------------------------------------
So your equation is y = 3/4x + 3
1/2b+2≤8
1/2b≤6
b≤12
Any number less than or equal to 12 can solve the equation.
The correct answer choices are B and C.
Here is the way these numbers would fall on a vertical number line justifying why these 2 answers are correct.
-1500 A
-1600
-1700
-1800
-1900 B
-2000
-2100
-2200
-2300 C
You can see where each of these submarines is located. 0 is sea level.