What’s your question tho ?
$1.50C + $4A= $5050
C + A = 2200
-4(C + A = 2200)
-4C - 4A = -8800
1.50C+4A = 5050
-----------------------
-2.5C =- 3750
-2.5C/-2.5 =- 3750/-2.5
C = 1500
C + A = 2200
1500 + A =2200
1500 - 1500 + A = 2200 - 1500
A = 700
CHECK
$1.50C + $4A= $5050
$1.50(1500) + $4(700)= $5050
$2250 +$2800 =$5050
$5050 = $5050
C + A = 2200
1500 + 700 =2200
2200 = 2200
Since OC is perpendicular to AB, the line AB gets split evenly. So

So AB=2*6.7=13.4
Ans: Option B, 13.4 units