Thanks BB and Mohater,
Solving and confirming on the ans choice is THE BEST. No argument on that. But, what I face is that under time pressure I somehow can bring down the choices to C and E but cannot decide on which one to pick. Obvisouly since time is running fast, I have to pick some.
So my questions is - is it a safe bet to pick C when the clues looks simple and choice E when the numbers looks little off or the clues give NO clue?
Most of the times, the correct ans is E when I am left with options C and E(I am taking abt the DS questions where my only choices are between C and E)
Anyhow, my obs from past couple of GMAT Prep questions says, that when I end in C / E in DS where I cannot decide, I will go with E.
After reading your responses, I felt that my questions is "THE DUMBEST"

Anyhow, thankyou once again for taking time to reply back.