Official Explanation:

This sentence contains a lot of double negatives and switchbacks. The big clue is “likely to be rejected by the board.” Another clue is that the board has “demonstrated a particular bent for progressive action.” This means the board is inclined to favor change or progress, which means the board would be likely to support any plans for a more environmentally conscious posture. So, if the board would support the environmentally conscious posture, and if the board is likely to vote down the new measure, this new measure must be against the plans for a more environmentally conscious posture. Therefore, the measure must be designed to “kill” or “prevent” the management team’s plans.

(A) Alter is a word that would fit in the blank. Since the proposed measure is against the management team’s plans, it’s reasonable to suggest that the measure would alter, or change, the plans. However, note that there is no synonym match for alter. Remember, we must always choose two answers that end up giving a similar meaning to the sentence.

(B) CORRECT. Scotch means “to put an end to, stamp out.” This is exactly what we want.

(C) Back, meaning “support,” is exactly the opposite of what we want.

(D) CORRECT. Foil means “to prevent the success of.” Again, this is perfect.

(E) Fund is not right. The measure is designed to destroy the plans, not fund them.

(F) Endorse, meaning “support,” is exactly the opposite of what we want.

One who gets turned around by the switchbacks would be likely to choose (C) and (F), a synonym pair with exactly the opposite meaning of what we want.