_________ are optional, clickable thumbnail images that appear next to TrueView InStream ads on YouTube.

Q)  _________ are optional, clickable thumbnail images that appear next to TrueView InStream ads on YouTube.

  A)  Companion banners.

  B)  TrueView in-display ads.

  C)  Display ads on the Google Display Network (GDN).

  D)  YouTube mastheads.