IMO B.

Rememeber that in Strengthen question ,the option that looks like the praphrased version of the passage is correct.

gist of the passage is - One telivision network, held its surveyresults until poll results. Because it did not want the votes to be biased.

(A) The network had endorsed the Republican candidate for President.
This weakens the argument. Because, it shows that the network withheld the results for some purpose other than that stated in the premise.

(B) The network expected its ratings to increase if it predicted the winner of the presidential race, and to decrease if did not predict the winner.
This option was intended in the passage but was not shown. Hence this strengthens the argument.
This option says even when the network knew that the ratings would decrease if it did not predict the winner, it did not do so.

(C) A rival network did predict a winner of the presidential race before the polls on the west coast closed.
This is out of scope.

(D) The network believed that it would receive higher ratings by not predicting the winner of the presidential race.
This again weakens the argument because, it shows another intent for not predicting the winner.

(E) The network feared that predicting the winner of the presidential race could so anger Congress that it might enact legislation preventing all future polling outside of voting centers.
Same reason as D. shows different intent for not predicting the winner.

pick B

hope this helps!!