The trick is to understand that the question really asks us for the odds that in a group of four workes (w1 - w4) ---> w1< w2 < w3 < w4.
Since we have four workers, the total possibable arrangements is 4! = 24 but in only one possibable arrangement can w1 < w2 < w3< w4 so the probability is 1/24.
Hence for any four workers chosen the probability is 1/24 , no matter how many workers we started with (just ignore the 99 number).
the answer is (D)