Answer:
A) With multiple headline and description options, responsive ads can compete in more auctions for a wider range of search terms.
C) With lower costs-per-click, advertisers using responsive ads can afford to be in more daily auctions.
Step-by-step explanation:
Google's responsive ads automatically adjust their appearance, format and size to fit in the available spaces that might show up in a website. Besides fitting on any spaces available, responsive ads can also adapt to the native format of the website.
Another advantage of responsive ads is that they are much cheaper than extended text ads, so the cost per click is much lower.