Which method would be recommended for an advertiser who is trying to increase the Quality Score of a low performing keyword?

A) Repeat the keyword as many times as possible in the ad text.
B) Delete the keyword and add the keyword to the campaign again
C) Modify the ad associated with that keyword to direct to a highly relevant landing page
D) Increase the daily budget for the campaign in which the keyword is located

Ans: 
C) Modify the ad associated with that keyword to direct to a highly relevant landing page