Answer:
Option A, The cost-per-click on ad extensions is lower than on a search ad headline
Explanation:
Ad extensions provide better user interactions options and they allow people to take direct action from the search results. Â
More clicks can easily be obtained through ad extension and make an add cost effective (by reducing the cost incurred per click) and appealing. Â With reduced cost per click, as extension also guarantee higher engagement for advertisers and hence increase influence and quality
Hence, option A is correct