Answers: (B), (C)

'Requiring split-second...' shows that those who are likely to delay should not become investment bankers. Or another way of looking at it: the career of an investment banker is not a good one for those who hesitate. The word viable means feasible, likely to succeed.

(A) forwardness is somebody who is bold in a social sense
(B) hesitation fits blank perfectly
(C) to dithering is to delay in making a decision
(D) prevarication is the act of speaking evasively as to avoid telling the truth
(E) wastefulness does not fit context
(F) obstinacy means stubbornness. While one who is stubborn may not be likely to make a split-second decision the word does not quite fit the context nor is there a matching word