The 1000SC questions are terrible for practice.
Not only....but also (eliminate all answers that do not have this construction
A,B,D are left
The differences between A&B are: 1) the comma after crash 2) the word "they" 3) "should" be expedited
B states the information more concisely/clearly then A in this respect because 1 & 2 aren't necessary and 3 is redundant.
D is wrong because "pilots' union's demands" is incorrect subject verb agreement.
My advice is to stop using the 1000SC garbage and pick up the OG! The OG has the best explanations and you will learn more after each incorrect answer instead of rolling the dice with this madness.