This is an absolute value problem.
Question:
IA-CI =5 and IB-CI = 20
St1 ) IA-BI = 25, there are two ways to get this
A-C + C-B OR C-A + B-C
For the first one A-C=5 and C-B=20 so A=5+C and C=B+20
B-----------C---------A
For the second one C-A =5 and B-C =20 so C=A+5 and B=C+20
A-----------C---------B
SUF
ST2) B-A > 0
From the given , we can get B-A as:
B-C + C-A = 20+5 or 20-5
So B-C = 20 and C-A=5 MEANS B=C+20 and C=A+5
A---C-------------B
OR
B-C = 20 and A-C= -5 MEANS B=C+20 and A=C-5
C---A------------B
INSUF
I would choose A and pray not to see this question in GMAT

LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"