Answer:
a. The ads adjust to available screen space when delivered.
Explanation:
"Responsive Display Ads" are considered the default format being used by Google Ads. This allows the advertiser to have more creativity when it comes to controlling their ads. Through the "machine learning technology," an artificial intelligence tool, the computer is able to learn about the things that correlate to the buying ability of the user. This will then automatically display the things or products which the users want.
The ads are capable of adjusting in order to fit any size, appearance or format. This means that they can adjust to available screen space. This is the reason why you can see one advertisement of a product as a banner while the other as a text.
So, this explains the answer.