Hi kamalakarthi,
In certain circumstance - when TESTing VALUES - it's sometimes best to 'target' a particular answer and try to select values that will directly eliminate it (as opposed to randomly selecting values and seeing what happens).
With these answer choices, it also helps to break each answer into 2 parts: the first absolute value and whatever is subtracted from it.
For Answers A, B and C, you should look to make the first part equal 0 and the second part NOT 0....
Answer A: A = 1, B = -1 ... |1 - 1| - |1 - (-1)| = 0 - 2 = -2 Eliminate Answer A.
Answer B: A = 1, B = -1 .... |1 - 1| - |1| = 0 - 1 = -1 Eliminate Answer B.
Answer C: A = 1, B = -2.... |2 - 2| - |1 -2| = 0 - 1 = -1 Eliminate Answer C.
For the remaining two answers, since you're dealing with exponents, you should consider fractions....
Answer E: A = 1/2, B = 1/2 ... |(1/2)^3 + (1/2)^3| - 1/2 - 1/2 = 2/8 - 1 = -6/8 Eliminate Answer E.
Final Answer: D
GMAT assassins aren't born, they're made,
Rich